Expose attribution manager as public API

[tobrun]

Closes #10932, this PR allows the Android SDK to have parity with the iOS SDK in terms of showing the attribution dialog on demand. On top of this, custom instances of AttributionDialogManager can be created and hooked into the attribution click with:

findViewById(R.id.attributionView).setOnClickListener(yourAwesomeAttribtionManager);

This allows to override the protected showAttributionDialog and provide a custom implementation.

[LukasPaczos]

Would it make sense to expose it even further by adding a setter in the UiSettings?

[tobrun]

@LukasPaczos what kind of API do you have in mind for that?

[LukasPaczos]

@tobrun I was thinking about UiSettings#setAttributionDialogManager(AttributionDialogManager myAttributionDialogManager), or just UiSettings#setOnAttributionDialogShownListener(). To give better idea how to handle this situation without digging through layout files.

[tobrun]

@LukasPaczos I added the suggested API in 78714e3. Care to re-review?

[LukasPaczos]

@tobrun thanks for including the setter. 🚢