Authorize screen for OAuth 2.0 apps: is not mobile friendly

Summary

Using mobile device and when using OAuth 2 app to login in 3rd party service. The app is asking authorization even if the app is trusted. The accept button is rendered out of the screen and mobile has to be turned into landscape mode to push the button.

Steps to reproduce

1. try to use Oauth2 app from mobile in a browser.
2. login to Mattermost in the mobile browser
3. authorize screen appears even if the app is se to Trusted
4. you cannot push the "allow" button as it is not shown in the screen
5. only way to use it now is to turn mobile to to landscape orientation
6. push allow.

Expected behavior

The allow button should be clickable in mobile portrait mode or the authorize screen should not appear at all because the app is set to Trusted

Observed behavior (that appears unintentional)

Authorize screen is shown even if the app se set to trusted. Authorize screens allow button is rendered outside the mobile screen and scrollbars are not provided. Page is not mobile friendly.

Possible fixes

Make Oauth2 authorize screen mobile friendly.