fix keyboard layout OSD on X

OSD for alternative shortcut has been removed in 9021b3cb,
because that approach don't work well with new layout applet.

New approach intends to make OSD behavior almost identical on X11/
Wayland - OSD should only pop up on keyboard shortcut and not on the
applet click/mouse wheeling.

Also, it implements OSD for the Main shortcut.

BUG: 408928
2 jobs for !491 with work/bam/OSD in 3 minutes and 3 seconds (queued for 65 minutes and 18 seconds)
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