Expose gesture recognizers directly on MapView.GestureManager

[nishant-karajgikar]

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Fixes: < Link to related issues that will be fixed by this pull request, if they exist >

Pull request checklist:

• Briefly describe the changes in this PR.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality. If tests were not written, please explain why.
• Add example if relevant.
• Document any changes to public APIs.
• Apply changelog label ('breaking change', 'bug 🪲', 'build', 'docs', 'feature 🍏', 'performance ⚡', 'testing 💯') or use the label 'skip changelog'
• Add an entry inside this element for inclusion in the mapbox-maps-ios changelog: <changelog>Gesutre Recognizers added to the mapView are exposed as properties on mapView.gestures</changelog>.
• Update the migration guide, API Docs, Markdown files - Readme, Developing, etc

Summary of changes

This PR adds computed vars to the public interface of MapView.GestureManager which allow for a developer to inspect (and potentially become the GestureRecognizerDelegate of) stock gestures that are set on the map.

[macdrevx]

What do you think of making the property types simply UIGestureRecognizer that way we're less tied to a specific implementation?

[nishant-karajgikar]

What do you think of making the property types simply UIGestureRecognizer that way we're less tied to a specific implementation?

Yep, I'm not opposed to that. Will update.