Add more screenshot of the running shell to the tests

Add the OSD and the run dialog which already exposed a bug regarding setting the title (also fixed in this MR). While at that shorten the DBus names of the affected DBus protocol according to the current pattern.

Basically a side project of !1179 (merged) but as there's no functional overlap, let's have it separate.

Signed-off-by: Guido Günther agx@sigxcpu.org