* Move isOnlyEmoji out of RichText
To fix Fast Refresh.
* Make renderChildrenWithEmoji work with any children
* Always go through UITextView for consistency
It already contains the `selectable` and `iOS` checks inside.
* Move `emoji` check into `renderChildrenWithEmoji`
* Remove unnecessary intermediate UITextView nodes
* Make childHasEmoji check recursive
It didn't handle nested arrays etc correctly before.
* Remove the "children must be string" limitation
Should not be necessary now that we correctly handle nested arrays etc.
* Fix unnecessary regex reallocation
This doesn't have a global flag so it's okay to reuse.
* Remove unnecessary <Text> wrapper in RichText
Eric Bailey