screenshot-application: Use accel for help

Code was duplicated across both dialogs to handle the F1 shortcut for help. This is now handled as an accel for the app.help action.
1 job for wip/christopherdavis/screenshot-redesign in 4 minutes and 8 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #625334
flatpak
flatpak

00:04:08