Fix trace flags type from i32 to u32 in Geneva exporter

[Copilot]

This PR fixes the trace flags field type in the Geneva exporter's OTLP encoder to use u32 instead of i32, aligning with the OpenTelemetry protobuf specification.

Changes Made

1. Updated field type definition: Changed BondDataType::BT_INT32 to BondDataType::BT_UINT32 for trace flags in the determine_fields() method
2. Updated value serialization: Changed log.flags as i32 to log.flags as u32 in the write_row_data() method
3. Added test coverage: Added test_trace_flags_uint32_type() to verify the fix works correctly

Background

The issue was identified during code review where it was noted that trace flags should be unsigned 32-bit integers according to the OpenTelemetry protobuf specification, but the Geneva exporter was incorrectly treating them as signed 32-bit integers.

Testing

• All existing tests continue to pass
• New test specifically validates that trace flags fields use the correct BT_UINT32 type
• Code compiles successfully with no warnings

The changes are minimal and surgical, affecting only the specific type handling for trace flags without impacting any other functionality.

Fixes #355.

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[linux-foundation-easycla]

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[lalitb]

Unit-test is not required. also check the lint.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 49.5%. Comparing base (106d201) to head (14172ad).

Files with missing lines	Patch %	Lines
...eneva-uploader/src/payload_encoder/otlp_encoder.rs	0.0%	2 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff          @@
##            main    #356   +/-   ##
=====================================
  Coverage   49.5%   49.5%           
=====================================
  Files         67      67           
  Lines       8909    8909           
=====================================
  Hits        4413    4413           
  Misses      4496    4496           

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[Copilot]

Unit-test is not required. also check the lint.

Removed the unit test and fixed the linting issue (unnecessary cast warning). All linting checks now pass. Changes in commit 14172ad.