When editing an event, that already has attendees a user can “Compose (a) message’ from the button with the same name. Unfortunately one can not start writing immediately, before not focusing the textarea manually by even a mouse click or pushing tab two times.

Description of the Change

This PR sets focus to the textarea, immediately after the modal is opened.

Closes #751

How to test the Change

1. Edit an event, that already has attendees
2. Click 'Compose message' button
3. Start writing into the text field
   (without the need to click into the field or tab to the field)

Changelog Entry

Changed - Focus on message ‘textarea’ after pressing ‘Compose message’ button

Credits

Props @carstingaxion

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.