[STF] Move only_convertible_or to reserved namespace

[caugonnet]

Description

Move only_convertible_or utility in the reserved namespace

closes

Checklist

• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[copy-pr-bot]

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[caugonnet]

/ok to test 896b25a

[github-actions]

🟩 CI finished in 49m 25s: Pass: 100%/32 | Total: 8h 18m | Avg: 15m 35s | Max: 33m 26s | Hits: 60%/15390

• 🟩 cudax: Pass: 100%/28 | Total: 8h 04m | Avg: 17m 17s | Max: 33m 26s | Hits: 60%/15390

  🟩 cpu
    🟩 amd64              Pass: 100%/24  | Total:  7h 01m | Avg: 17m 34s | Max: 33m 26s | Hits:  62%/13018 
    🟩 arm64              Pass: 100%/4   | Total:  1h 02m | Avg: 15m 37s | Max: 16m 53s | Hits:  51%/2372  
  🟩 ctk
    🟩 12.0               Pass: 100%/3   | Total: 39m 59s | Avg: 13m 19s | Max: 15m 38s | Hits:  60%/1474  
    🟩 12.9               Pass: 100%/25  | Total:  7h 24m | Avg: 17m 46s | Max: 33m 26s | Hits:  60%/13916 
  🟩 cudacxx
    🟩 nvcc12.0           Pass: 100%/3   | Total: 39m 59s | Avg: 13m 19s | Max: 15m 38s | Hits:  60%/1474  
    🟩 nvcc12.9           Pass: 100%/25  | Total:  7h 24m | Avg: 17m 46s | Max: 33m 26s | Hits:  60%/13916 
  🟩 cudacxx_family
    🟩 nvcc               Pass: 100%/28  | Total:  8h 04m | Avg: 17m 17s | Max: 33m 26s | Hits:  60%/15390 
  🟩 cxx
    🟩 Clang14            Pass: 100%/2   | Total: 28m 58s | Avg: 14m 29s | Max: 16m 03s | Hits:  52%/1188  
    🟩 Clang15            Pass: 100%/1   | Total: 16m 27s | Avg: 16m 27s | Max: 16m 27s | Hits:  52%/593   
    🟩 Clang16            Pass: 100%/1   | Total: 17m 13s | Avg: 17m 13s | Max: 17m 13s | Hits:  52%/593   
    🟩 Clang17            Pass: 100%/1   | Total: 17m 31s | Avg: 17m 31s | Max: 17m 31s | Hits:  52%/593   
    🟩 Clang18            Pass: 100%/1   | Total: 16m 45s | Avg: 16m 45s | Max: 16m 45s | Hits:  52%/593   
    🟩 Clang19            Pass: 100%/4   | Total:  1h 14m | Avg: 18m 42s | Max: 26m 55s | Hits:  64%/2372  
    🟩 GCC10              Pass: 100%/2   | Total: 33m 40s | Avg: 16m 50s | Max: 18m 02s | Hits:  51%/1188  
    🟩 GCC11              Pass: 100%/1   | Total: 18m 11s | Avg: 18m 11s | Max: 18m 11s | Hits:  51%/593   
    🟩 GCC12              Pass: 100%/1   | Total: 21m 30s | Avg: 21m 30s | Max: 21m 30s | Hits:  51%/593   
    🟩 GCC13              Pass: 100%/8   | Total:  2h 07m | Avg: 15m 58s | Max: 23m 57s | Hits:  63%/4744  
    🟩 MSVC14.39          Pass: 100%/1   | Total: 11m 26s | Avg: 11m 26s | Max: 11m 26s | Hits:  95%/288   
    🟩 MSVC14.43          Pass: 100%/3   | Total: 34m 08s | Avg: 11m 22s | Max: 11m 30s | Hits:  95%/870   
    🟩 NVHPC25.5          Pass: 100%/2   | Total:  1h 05m | Avg: 32m 51s | Max: 33m 26s | Hits:  49%/1182  
  🟩 cxx_family
    🟩 Clang              Pass: 100%/10  | Total:  2h 51m | Avg: 17m 10s | Max: 26m 55s | Hits:  56%/5932  
    🟩 GCC                Pass: 100%/12  | Total:  3h 21m | Avg: 16m 45s | Max: 23m 57s | Hits:  59%/7118  
    🟩 MSVC               Pass: 100%/4   | Total: 45m 34s | Avg: 11m 23s | Max: 11m 30s | Hits:  95%/1158  
    🟩 NVHPC              Pass: 100%/2   | Total:  1h 05m | Avg: 32m 51s | Max: 33m 26s | Hits:  49%/1182  
  🟩 gpu
    🟩 h100               Pass: 100%/2   | Total: 19m 29s | Avg:  9m 44s | Max: 12m 51s | Hits:  75%/1186  
    🟩 rtx2080            Pass: 100%/26  | Total:  7h 44m | Avg: 17m 52s | Max: 33m 26s | Hits:  59%/14204 
  🟩 jobs
    🟩 Build              Pass: 100%/25  | Total:  7h 06m | Avg: 17m 04s | Max: 33m 26s | Hits:  55%/13611 
    🟩 Test               Pass: 100%/3   | Total: 57m 30s | Avg: 19m 10s | Max: 26m 55s | Hits:  99%/1779  
  🟩 sm
    🟩 90                 Pass: 100%/2   | Total: 19m 29s | Avg:  9m 44s | Max: 12m 51s | Hits:  75%/1186  
    🟩 90;90a             Pass: 100%/2   | Total: 26m 48s | Avg: 13m 24s | Max: 15m 21s | Hits:  66%/883   
    🟩 100;120            Pass: 100%/2   | Total: 26m 54s | Avg: 13m 27s | Max: 15m 43s | Hits:  66%/883   
  🟩 std
    🟩 17                 Pass: 100%/3   | Total:  1h 02m | Avg: 20m 48s | Max: 32m 17s | Hits:  51%/1777  
    🟩 20                 Pass: 100%/25  | Total:  7h 01m | Avg: 16m 52s | Max: 33m 26s | Hits:  61%/13613 
  

• 🟩 packaging: Pass: 100%/4 | Total: 14m 44s | Avg: 3m 41s | Max: 4m 04s

  🟩 cpu
    🟩 amd64              Pass: 100%/4   | Total: 14m 44s | Avg:  3m 41s | Max:  4m 04s
  🟩 ctk
    🟩 12.0               Pass: 100%/2   | Total:  7m 10s | Avg:  3m 35s | Max:  4m 04s
    🟩 12.9               Pass: 100%/2   | Total:  7m 34s | Avg:  3m 47s | Max:  4m 01s
  🟩 cudacxx
    🟩 nvcc12.0           Pass: 100%/2   | Total:  7m 10s | Avg:  3m 35s | Max:  4m 04s
    🟩 nvcc12.9           Pass: 100%/2   | Total:  7m 34s | Avg:  3m 47s | Max:  4m 01s
  🟩 cudacxx_family
    🟩 nvcc               Pass: 100%/4   | Total: 14m 44s | Avg:  3m 41s | Max:  4m 04s
  🟩 cxx
    🟩 Clang14            Pass: 100%/1   | Total:  3m 06s | Avg:  3m 06s | Max:  3m 06s
    🟩 Clang19            Pass: 100%/1   | Total:  3m 33s | Avg:  3m 33s | Max:  3m 33s
    🟩 GCC12              Pass: 100%/1   | Total:  4m 04s | Avg:  4m 04s | Max:  4m 04s
    🟩 GCC13              Pass: 100%/1   | Total:  4m 01s | Avg:  4m 01s | Max:  4m 01s
  🟩 cxx_family
    🟩 Clang              Pass: 100%/2   | Total:  6m 39s | Avg:  3m 19s | Max:  3m 33s
    🟩 GCC                Pass: 100%/2   | Total:  8m 05s | Avg:  4m 02s | Max:  4m 04s
  🟩 gpu
    🟩 rtx2080            Pass: 100%/4   | Total: 14m 44s | Avg:  3m 41s | Max:  4m 04s
  🟩 jobs
    🟩 Test               Pass: 100%/4   | Total: 14m 44s | Avg:  3m 41s | Max:  4m 04s
  

👃 Inspect Changes

Modifications in project?

	Project
	CCCL Infrastructure
	CCCL Packaging
	libcu++
	CUB
	Thrust
+/-	CUDA Experimental
	stdpar
	python
	CCCL C Parallel Library
	Catch2Helper

Modifications in project or dependencies?

	Project
	CCCL Infrastructure
+/-	CCCL Packaging
	libcu++
	CUB
	Thrust
+/-	CUDA Experimental
	stdpar
	python
	CCCL C Parallel Library
	Catch2Helper

🏃‍ Runner counts (total jobs: 32)

#	Runner
17	linux-amd64-cpu16
6	linux-amd64-gpu-rtx2080-latest-1
4	linux-arm64-cpu16
4	windows-amd64-cpu16
1	linux-amd64-gpu-h100-latest-1