(bug) - Add synchronization to Dir.chdir in init_puppet_lint

[jordanbreen28]

Summary

This PR wraps the Dir.chdir call in the validation_provider.rb file within a $PuppetParserMutex.synchronize block.

Before this change, the Dir.chdir method was called without synchronization, which could lead to conflicts if another chdir block was in progress.

This change prevents the error "(puppet/fixDiagnosticErrors) conflicting chdir during another chdir block" by ensuring that the Dir.chdir call is only executed by one thread at a time.

Additional Context

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• [ ] Root cause and the steps to reproduce. (If applicable)
• [ ] Thought process behind the implementation.

Related Issues (if any)

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Checklist

• [ ] 🟢 Spec tests.
• [ ] 🟢 Acceptance tests.
• [x] Manually verified.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes are missing coverage. Please review.

Project coverage is 11.69%. Comparing base (2a7db14) to head (fb4bc1d).

Files	Patch %	Lines
...pet-languageserver/manifest/validation_provider.rb	0.00%	3 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #374 +/- ## ========================================== - Coverage 11.69% 11.69% -0.01% ========================================== Files 92 92 Lines 11499 11501 +2 ========================================== Hits 1345 1345 - Misses 10154 10156 +2 ```

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