Insert text when current text is empty to preserve formatting when pasting to empty edit text

[planarvoid]

Fix

In this PR I'm replacing the functionality when pasting text into the empty aztec editor. Currently this triggers setText which removes all the formatting spans. However, I think it's a valid use case to turn on formatting and paste text and expect the pasted text to be formatted. Otherwise the functionality remains unchanged

Test

1. Set EXAMPLE field in the MainActivity to <h1></h1>
2. Run the app
3. Paste text to the editor
4. Notice it gets formatted with h1 (previously it didn't keep the formatting)

Review

@AmandaRiu

Make sure strings will be translated:

• [x] If there are new strings that have to be translated, I have added them to the client's strings.xml as a part of the integration PR.