feat: Include structured log message arguments as context data for MEL

[nr-ahemsath]

Description

Fixes #2519

When using Microsoft.Extensions.Logging (MEL) with structured logging (e.g., logger.LogInformation("User {UserId} did {Action}", userId, action)), the named parameters are now extracted from the TState state parameter and merged into context data. This makes them available as individual log attributes in New Relic (e.g., context.UserId, context.Action), matching the behavior already available for Serilog and NLog.

The state extraction is wrapped in its own try/catch to ensure it cannot disrupt existing scope-based context data harvesting. The {OriginalFormat} key (the message template string) is excluded.

Testing

Adds StructuredLogArgContextDataTests that verifies structured log message arguments (e.g., {Name}, {Id}) are extracted as context data attributes for supported use cases:

• MEL by itself
• MEL with Serilog
• MEL with NLog
• Serilog by itself
• NLog by itself

Log4Net is purposefully not tested because it doesn't support structured logging.

Additionally, some refactoring of the logging testing system is done for clarity, particularly around which testing frameworks are supported in which TFMs we build the ConsoleMF system for, and making the main code path for logging messages in LoggingTester easier to understand (there was a lot of entanglement with the context data dictionary logging path which is only used by one set of tests).

Co-authored by @piekstra

Author Checklist

• Unit tests, Integration tests, and Unbounded tests completed
• Performance testing completed with satisfactory results (if required)

Reviewer Checklist

• Perform code review
• Pull request was adequately tested (new/existing tests, performance tests)

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.77%. Comparing base (871f063) to head (e5089b0).
⚠️ Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3479      +/-   ##
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- Coverage   81.79%   81.77%   -0.02%     
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  Files         508      508              
  Lines       34220    34220              
  Branches     4040     4040              
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- Hits        27990    27984       -6     
- Misses       5265     5269       +4     
- Partials      965      967       +2     

Flag	Coverage Δ
Agent	82.76% <ø> (-0.02%)	⬇️
Profiler	71.75% <ø> (ø)

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