Fix waiting on caret rect detection when caret is at the end

[pinarol]

This PR fixes the waiting when we tap at the end of the text. Not sure about the root cause but it seems like caret y position can not be determined when it is at the end of the text. There are some similar issues on the web but no solutions. So this is a workaround but we can happily fallback to scrolling till the bottom of the component when caret is at the end anyway. And it is already what JS side does when we can't detect caret's position.

Problematic case:

Will add WPiOS PR here.

TO TEST:

• Check out branch at Update react-native-keyboard-aware-scroll-view ref WordPress-iOS#11116
• Tap at the end of a paragraph block
• Verify there's no delay

Also:

• test typing in the middle of the block and verify we can follow caret to the newlines
• test with merging/splitting blocks and verify we don't lose caret under the keyboard

[etoledom]

Looks good and works well ✨
Thanks for fixing this!