Initialize the native Rollbar/Android SDK as a hook instead of explicitly

[matux]

Description of the change

This PR encapsulates the initialization of the Rollbar/Android (native) SDK as another Hook, called the NativeHook.

This PR also encapsulate inside the PlatformHook the as dynamic hack we use to check whether the PlatformDispatcher.onError closure exists.

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

• Related to SC-129017

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.