[timob-16893]: Android update doc and behavior for 'enableReturnKey' property

Testing steps in JIRA
This is already the case in the current codebase, I only move this check up so we don't fire the return event. I think this is correct behavior since the docs for TextArea says: If true, the return key is disabled when this text area is empty, and automatically enabled as soon as the user types any text in the area.