馃崚 applets/userswitcher: Fit dialog height to content
This is done by checking implicitHeight (amount of users logged in) against one-third of the screen height (sane maximum). Overflow becomes scrollable list.
(cherry picked from commit 10d404a2)
0a454faa applets/userswitcher: Fit dialog height to content
Co-authored-by: Blazer Silving breakingspell@gmail.com