adding test for trace_function decorator

[M-Hietala]

adding test for trace_function decorator

[Copilot]

Pull request overview

This PR adds comprehensive test coverage for the trace_function decorator, which is used to trace function calls using OpenTelemetry. The PR includes both synchronous and asynchronous test suites, along with minor improvements to the underlying implementation.

Changes:

• Added comprehensive test suite for synchronous functions with the trace_function decorator
• Added comprehensive test suite for asynchronous functions with the trace_function decorator
• Improved the implementation to use inspect.iscoroutinefunction instead of asyncio.iscoroutinefunction
• Fixed the parameter sanitization logic to correctly handle positional arguments, keyword arguments, and default values
• Enhanced tracer initialization to occur at function execution time rather than decoration time

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
sdk/ai/azure-ai-projects/tests/agents/telemetry/test_trace_function_decorator.py	New test file with 13 comprehensive test cases for synchronous functions, covering primitives, collections, custom span names, exceptions, and mixed parameter types
sdk/ai/azure-ai-projects/tests/agents/telemetry/test_trace_function_decorator_async.py	New test file with 15 comprehensive test cases for asynchronous functions, mirroring sync tests plus additional coverage for default parameters
sdk/ai/azure-ai-projects/azure/ai/projects/telemetry/_trace_function.py	Implementation improvements: changed from asyncio to inspect for coroutine detection, moved tracer initialization to execution time, and fixed parameter handling logic