[6/n] Native Typeahead - Refactor focusAndUpdateText and add focusAndUpdateTextAndSelection

Summary:
Preparing for native typeahead.
Refactored utility funtion used for focusing text input and introduced new function that will be used in typeahead. Common part was extrated to focusAndHandleButtons.

Test Plan:
Checked if app builds.
Tested if focusing on reply still works correctly.
focusAndUpdateTextAndSelection tested in future diffs when it's actually used.

Reviewers: inka, ginsu, kamil, michal, tomek, ashoat

Reviewed By: tomek, ashoat

Subscribers: ashoat, tomek, atul, inka, ginsu, kamil, michal

Differential Revision: https://phab.comm.dev/D6368