Fail when detecting wrong desktop

After performing wide search in OSD/O3 to find scenarios where
we were displaying info box about mismatching, now we can die
when detecting wrong desktop and at the same time
improve a bit the validation to assert expected vs actual result.
hmc/pvm_hmc excluded at the moment due to problems switching tty.

tests/installation/installation_overview.pm

@@ -22,7 +22,7 @@ use warnings;
 use testapi;
 use version_utils qw(is_caasp is_upgrade);
 use Utils::Backends qw(is_remote_backend is_hyperv);
-
+use Test::Assert ':all';
 
 sub ensure_ssh_unblocked {
     if (!get_var('UPGRADE') && is_remote_backend) {
@@ -79,18 +79,7 @@ sub run {
                 assert_screen 'inst-xen-pattern';
             }
         }
-        ensure_ssh_unblocked;
-        # Check the systemd target, see poo#45020
-        # We need to exclude some scenarios where it doesn't work well
-        return if (is_caasp || is_upgrade || is_hyperv || get_var('REMOTE_CONTROLLER'));
-        if (get_var('DESKTOP')) {
-            my $target = check_var('DESKTOP', 'textmode') ? "multi-user" : "graphical";
-            select_console 'install-shell';
-            # The default.target is not yet linked, so we have to parse the logs.
-            script_run("grep 'target has been set' /var/log/YaST2/y2log |tail -1 |grep --color=auto \"$target\"")
-              && record_info("Warning: no target", "Could not detect the systemd target. Expected was: $target (see poo#49622).");
-            select_console 'installation';
-        }
+        check_default_target;
     }
 }