#Mail: Message action buttons should only be enabled when a message is selected

[gtandersen]

Describe the bug
When clicking any of the message action buttons without one or more messages being selected, no action is performed or an error is produced. The buttons should only be enabled when one or more messages are selected.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://runbox.com/app
2. Click on e.g. the "Trash" or "Mark unread" button.
3. Observe that no action is performed or an error is produced.

Expected behavior
The message action buttons should be disabled and greyed out, and not be clickable, until at least one message has been selected.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: macOS
• Browser: Safari