mainWindow: Only enable map type shortcuts when useful

Only enable the shortcuts to switch b/w street and aerial
map types when aerial tiles are available.
2 jobs for master in 9 minutes and 28 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
canceled #1329246
flatpak
flatpak

00:09:28

 
  Deploy
canceled #1329247
nightly