[camera_android_camerax] Updates pigeon generation to prevent crash when objects call to Dart after a hot restart

[bparrishMines]

Fixes flutter/flutter#176451

Pre-Review Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene page, which explains my responsibilities.
• I read and followed the relevant style guides and ran the auto-formatter.
• I signed the CLA.
• The title of the PR starts with the name of the package surrounded by square brackets, e.g. [shared_preferences]
• I linked to at least one issue that this PR fixes in the description above.
• I updated pubspec.yaml with an appropriate new version according to the pub versioning philosophy, or I have commented below to indicate which version change exemption this PR falls under¹.
• I updated CHANGELOG.md to add a description of the change, following repository CHANGELOG style, or I have commented below to indicate which CHANGELOG exemption this PR falls under¹.
• I updated/added any relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or I have commented below to indicate which test exemption this PR falls under¹.
• All existing and new tests are passing.

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[gemini-code-assist]

Code Review

This pull request fixes a crash that occurs when native objects call to Dart after a hot restart. The fix involves updating the pigeon dependency and regenerating the CameraXLibrary.g.kt file. The new generated code correctly adds checks to verify the existence of native instances before making callbacks to Dart. The CHANGELOG.md and pubspec.yaml files are also updated appropriately.

The code changes are correct, but the pull request does not fully adhere to the repository's contribution guidelines. Please update the pull request title to [camera_android_camerax] fix crash and fill out the PR description, including the checklist and a link to the issue this PR resolves.