Steps to reproduce:

1. Navigate to Alerts -> Media types
2. Press on "Disabled" status button of the media type Gmail (or Office365)
3. Observe error message "Cannot enable media type. Incomplete configuration: Gmail"
4. Open the Gmail media type, check the "Enabled" checkbox and do not change anything else
5. Click Update
6. Observe status changed without error messages

Result: error message about incomplete configuration present if Gmail and Office365 media types enabled from list
Expected: no error message should be displayed to ensure consistent behaviour since the same action done from form does not create error