[OpenTelemetry] Update wildcard regex

[martincostello]

Changes

• Disable backtracking in modern .NET.
• Add match timeout when targeting .NET Framework.

Found by a scan of the repository code using Claude Code.

Merge requirement checklist

• CONTRIBUTING guidelines followed (license requirements, nullable enabled, static analysis, etc.)
• Unit tests added/updated
• Appropriate CHANGELOG.md files updated for non-trivial changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.86%. Comparing base (7dbd68d) to head (cec6241).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7760   +/-   ##
=======================================
  Coverage   91.85%   91.86%           
=======================================
  Files         337      337           
  Lines       18399    18410   +11     
=======================================
+ Hits        16901    16912   +11     
  Misses       1498     1498           

Flag	Coverage Δ
unittests-Project-Experimental	91.92% <100.00%> (-0.06%)	⬇️
unittests-Project-Stable	91.94% <100.00%> (-0.02%)	⬇️

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Files with missing lines	Coverage Δ
src/OpenTelemetry/Internal/WildcardHelper.cs	100.00% <100.00%> (ø)
.../Metrics/Builder/MeterProviderBuilderExtensions.cs	98.57% <100.00%> (+0.04%)	⬆️
src/OpenTelemetry/Metrics/MeterProviderSdk.cs	92.91% <100.00%> (ø)
src/OpenTelemetry/Trace/TracerProviderSdk.cs	97.36% <100.00%> (ø)

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[Copilot]

🟢 Approval recommended

The implementation is consistent and regression-tested; only minor changelog wording needs correction.

Review details

• Files reviewed: 6/6 changed files
• Comments generated: 1
• Review effort level: Balanced