Use new PlatformDispatcher onError method if available

[matux]

Description of the change

This PR implements the new recommended method to catch exceptions that don't occur within Flutter's callbacks according to https://docs.flutter.dev/testing/errors.

This swizzles the PlatformDispatcher.onError callback with our own callback which also calls the original one.

Previously, we were using a custom Zone to catch this class of exceptions but it was deprecated in Flutter 3.3.

We aim to preserve compatibility with Flutter < 3.3.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Maintenance
• New release

Related issues

• Resolves SC-129017.
• Closes Starting from Flutter 3.3 catching errors via PlatformDispatcher.onError is now the recommended approach. #101.
• Partial RollbarFlutter.run is limiting (and probably not working as intended) #90.

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers assigned
• Issue from task tracker has a link to this pull request
• Changes have been reviewed by at least one other engineer

[shortcut-integration]

This pull request has been linked to Shortcut Story #129017: Flutter SDK isn't catching async errors.