enhance: [cherry-pick] fix otel config param type & leak

[congqixia]

cherry pick from master
pr: #29810 #30055

SampleFraction shall be float and all C.CString shall be freed

[sre-ci-robot]

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[mergify]

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[congqixia]

/run-cpu-e2e

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (9aceff5) 82.14% compared to head (674f259) 82.21%.
Report is 1 commits behind head on 2.3.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.3   #30068      +/-   ##
==========================================
+ Coverage   82.14%   82.21%   +0.07%     
==========================================
  Files         834      825       -9     
  Lines      120991   120345     -646     
==========================================
- Hits        99387    98945     -442     
+ Misses      18382    18176     -206     
- Partials     3222     3224       +2     

Files	Coverage Δ
internal/util/initcore/init_core.go	86.51% <100.00%> (+1.51%)	⬆️

... and 124 files with indirect coverage changes

[yah01]

/lgtm