fix: [2.4] Fix tracing config update logic (#35928)

[congqixia]

Cherry-pick from master
pr: #35928
Related to #35927

There are serveral issue this PR addresses:

• Use ResetTraceConfig method instead init one in update event handler
• Implement dynamic stats.Handler to receive tracing config update event
• Update enable_trace flag when ResetTraceConfig is invoked
• Change enable_trace to std::atomic<bool> in case of data race

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

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[congqixia]

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[codecov]

Codecov Report

Attention: Patch coverage is 65.33333% with 26 lines in your changes missing coverage. Please review.

Project coverage is 81.18%. Comparing base (6158ad3) to head (0e71f35).
Report is 13 commits behind head on 2.4.

Files with missing lines	Patch %	Lines
pkg/tracer/stats_handler.go	62.29%	19 Missing and 4 partials ⚠️
internal/core/src/common/Tracer.cpp	81.81%	2 Missing ⚠️
internal/util/grpcclient/client.go	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #35998      +/-   ##
==========================================
+ Coverage   71.92%   81.18%   +9.25%     
==========================================
  Files        1057     1058       +1     
  Lines      139105   139153      +48     
==========================================
+ Hits       100051   112965   +12914     
+ Misses      34779    21907   -12872     
- Partials     4275     4281       +6     

Files with missing lines	Coverage Δ
internal/distributed/datacoord/service.go	88.73% <ø> (-0.11%)	⬇️
internal/distributed/datanode/service.go	82.12% <ø> (-0.18%)	⬇️
internal/distributed/indexnode/service.go	74.66% <ø> (-0.34%)	⬇️
internal/distributed/proxy/service.go	85.19% <100.00%> (-0.03%)	⬇️
internal/distributed/querycoord/service.go	77.72% <ø> (-0.20%)	⬇️
internal/distributed/querynode/service.go	83.14% <ø> (-0.19%)	⬇️
internal/distributed/rootcoord/service.go	82.67% <ø> (-0.14%)	⬇️
internal/util/grpcclient/client.go	86.37% <50.00%> (+1.71%)	⬆️
internal/core/src/common/Tracer.cpp	77.77% <81.81%> (+77.77%)	⬆️
pkg/tracer/stats_handler.go	62.29% <62.29%> (ø)

... and 241 files with indirect coverage changes

[aoiasd]

/lgtm