Escape management in only one method

I've moved the leave full screen on escape from the media_viewer to the
existing escape method in to have all the behaviour in only one

Doing this I've also added the functionality to go back to the chat when
we're in the MediaViewer and to do this I've to modify a little the
autocomplete, to avoid the close when we press escape on the
autocomplete popover.

I've also changed the key management on key press instead of key release
because the keypress is grabbed by child windows or popovers and the
release isn't.

Close #277
1 job from master in 16 seconds (queued for 4 seconds)
Status Job ID Name Coverage
failed #56215


Name Stage Failure
flatpak Test
Cloning into '/builds/World/fractal'...
Checking out f74fbb57 as master...
Skipping Git submodules setup
Checking cache for flatpak...
Successfully extracted cache
$ flatpak-builder --stop-at=fractal app flatpak/org.gnome.Fractal.json
error: org.gnome.Sdk/x86_64/3.28 not installed
Failed to init: Unable to find sdk org.gnome.Sdk version 3.28
ERROR: Job failed: exit code 1