endSessionDialog: Fix hibernate action

[anaximeno]

closes #12664

Before the fix

end-session-dialog-hibernate-not-fix-1.mp4

Another issue that happens due to this, since the dialog stays open for longer and active is that as you can see in the video, I can click the other options and even the hibernate option more than once, which since the hibernation stores the state can lead to the system firing these actions (like a reboot) unecessarily (and unatended too likely) after the hibernation is resumed, like happened here:

end-session-dialog-hibernate-not-fix-2.mp4

After the fix

end-session-dialog-hibernate-fix.mp4

This was tested in a computer with LMDE 7.

[anaximeno]

Also not necessarily related to this PR (this should be good enough to fix the main issue happening in my view), is that during the hibernation something that can be confusing happens which is the screensaver appearing - then the screen goes dark (which gives the impression the hibernation has happened) - then the screensaver appearing again (which gives the impression the system has had some issue during the hibernation), to then in the end the hibernation taking the effect. This is something that happens regardless of my fix, and happened before iirc, however I'm not sure what causes it, so I just wanted to leave this here as a note.

[calestyo]

@anaximeno Good to see that merged… last time I tried to improve upon thee end session dialog, contribution wasn’t that welcomed.

I guess that the screen goes dark might simply be a kernel thing?!

[mtwebster]

I think it's an xserver timing/race issue - I've seen this on some machines and not others, nothing really consistent about it.