Fix disabled groups after screen rotation
isDissolved was reverted back to LiveData that only shows a dialog when the activity was first opened.
Test instructions:
- create or join private group, enter the group, rotate screen and ensure group doesn't get disabled/greyed out
- join private group shared by contact, let contact dissolve the group and ensure
- you get a dialog and the group gets disabled after the contact has dissolved the group
- the same happens if you re-enter the group again
- rotating the screen in the disabled group doesn't re-show the dialog
- the group is greyed out in the group list and removable there