Add context handling to sinks in consumertest

[vignesh-codes]

Description

This PR enhances the consumertest.Sink types (TracesSink, MetricsSink, LogsSink, ProfilesSink) to store and expose request contexts during consumption

Changes include:

• Added context storage to all sink types
• Added AllContexts() method to retrieve stored contexts
• Updated Reset() to clear stored contexts
• Added comprehensive tests for context transformation verification

Link to tracking issue

Fixes #13039

Testing

Added new test cases to verify context handling:

• TestSinkContextTransformation: Verifies context preservation across all sink types
• TestContextTransformationChain: Tests complex chains of context transformations
• TestConcurrentContextTransformations: Ensures thread-safe context handling
• Added context verification to existing sink tests

Documentation

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: vignesh-codes / name: Vignesh (Vinn) (eaa50b7, 3e3573f, 7477aa6, 80f6c3d)

[vignesh-codes]

Do we need changelog entry?

[dmathieu]

Do we need changelog entry?

This changes the package's public API, so yes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.55%. Comparing base (4a5e154) to head (eaa50b7).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #13048      +/-   ##
==========================================
+ Coverage   91.54%   91.55%   +0.01%     
==========================================
  Files         504      504              
  Lines       28157    28192      +35     
==========================================
+ Hits        25775    25810      +35     
  Misses       1873     1873              
  Partials      509      509              

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