ESourceSelector: Emit source-select/unselect on source change
Tested with Evolution 3.50.4 on Fedora 39, with GNOME Calendar 45.1 and 46 / nightly.
As you can see in this demonstration video, when I toggle the display of a calendar in EDS via GNOME Calendar, Evolution's calendaring UI sidebar successfully reflects the state in realtime, however the view forgets to update to match that; it only updates when toggling those checkboxes directly in Evolution's sidebar.
Evolution_3.50.4_and_calendars_display_toggled_by_external_apps
I think this used to work fine in previous versions of Evolution, but I'm not 110% sure.