fix: false positive for guarded call to LoggerMessage

[Thomas-Shephard]

Summary

Fixes a bug in the CA1873 analyzer where logging calls that were guarded by IsEnabled were being incorrectly flagged when using LoggerMessage.

Problem

The analyzer was not associating the Ilogger instance used in the IsEnabled check with the one used in LoggerMessage causing false positives even when the code was being guarded correctly.

Fixes #50893

Fix

Updated the AreInvocationsOnSameInstance logic to correctly identify whether this is the case.

Testing

Added a new test GuardedLoggerMessage_NoDiagnostic_CS and ensured all existing tests continue to pass

[Copilot]

Pull request overview

This PR fixes a false positive in the CA1873 analyzer where logging calls guarded by IsEnabled checks were incorrectly flagged when using LoggerMessage attribute-based logging methods.

Key Changes

• Updated AreInvocationsOnSameInstance method to recognize when a LoggerMessage method and an IsEnabled check are using the same logger instance
• Added special handling for both static LoggerMessage methods (with explicit logger parameter) and instance LoggerMessage methods (with captured logger from class members)
• Added test coverage for guarded LoggerMessage scenarios

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
AvoidPotentiallyExpensiveCallWhenLogging.cs	Enhanced logger instance matching logic to support LoggerMessage patterns, including heuristic for instance methods that capture loggers from class fields/properties/constructor parameters
AvoidPotentiallyExpensiveCallWhenLoggingTests.cs	Added test case for guarded LoggerMessage calls using both instance and static patterns with primary constructor parameters

[stephentoub]

Could this throw / crash if the code isn't well formed when the analyzer runs?

[Thomas-Shephard]

Good point, hopefully the latest commit should do the trick