Feedback widget - button should be disabled for empty input field

Created by: AlicjaSuska

##Description

It shouldn't be possible to send feedback without the message. Currently, after selecting the emoji, the button is enabled.

To prevent getting meaningless messages with emoji only, I think we should enable the button when both conditions are met:

• the emoji is selected
• the message (input field) is not empty

Note: the behaviour hasn't changed because of the refresh changes. It is this way in the current implementation.