Drop kmag test on F40+

kmag was removed in
https://pagure.io/fedora-comps/c/bb332b310b22a1103347afece6f845087694d85e?branch=main
we can't drop the test entirely yet as it's still in F39. Will
drop this after F39 is released.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

tests/apps_startstop/kde/kmag.pm

@@ -7,6 +7,9 @@ use utils;
 
 sub run {
     my $self = shift;
+    # FIXME after F39 is stable, drop this test entirely
+    my $relnum = get_release_number;
+    return unless ($relnum < 40);
 
     # Start the application
     menu_launch_type 'kmag';