Merge relevant commits to rc-bridge from main

[alexvru]

• Improve brigded group proxy a bit (Improve brigded group proxy a bit #24539)
• Refactor dstool cluster workload run cmd to restart nodes correctly (Refactor dstool cluster workload run cmd to restart nodes correctly #24542)
• Correct FreeUpToLsn interpretation (Correct FreeUpToLsn interpretation #24552)
• Some TestShard improvements and fixes (Some TestShard improvements and fixes #24896)
• Stop gRPC server when in DISCONNECTED state (Stop gRPC server when in DISCONNECTED state #24939)
• Allow missing blobs in IndexRestoreGet query (Allow missing blobs in IndexRestoreGet query #25030)
• Optimize TEvAssimilate (Optimize TEvAssimilate #25084)

[github-actions]

⚪ 2025-09-17 05:44:21 UTC Pre-commit check linux-x86_64-release-asan for 5f1e83d has started.
⚪ 2025-09-17 05:44:37 UTC Artifacts will be uploaded here
⚪ 2025-09-17 06:10:15 UTC ya make is running...
🟡 2025-09-17 08:56:16 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
17040	16492	0	174	344	30

🟢 2025-09-17 08:57:43 UTC Build successful.

[github-actions]

⚪ 2025-09-17 05:45:04 UTC Pre-commit check linux-x86_64-relwithdebinfo for 5f1e83d has started.
⚪ 2025-09-17 05:45:18 UTC Artifacts will be uploaded here
⚪ 2025-09-17 06:10:21 UTC ya make is running...
🟡 2025-09-17 08:12:29 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
39705	36948	0	3	2712	42

⚪ 2025-09-17 08:15:58 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-09-17 08:29:55 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
373 (only retried tests)	346	0	0	0	27

🟢 2025-09-17 08:30:04 UTC Build successful.