Make g-i-s Start Setup button needle its own thing

There's a race issue with just treating it as a next button: it's
not in the same place as a next button. Sometimes in the g-i-s
code we actually get ahead of ourselves and click early, which
isn't really a problem when the buttons are all in the same
place, but if we click "Start Setup" in the middle of transition
to the Privacy screen - as in
https://openqa.fedoraproject.org/tests/745034#step/_graphical_wait_login/4
 - the click effectively gets lost. So let's make it its own tag
and have the initial assert look for it too. That way we won't
match on it again in the main loop over "@nexts".

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

lib/utils.pm

@@ -693,10 +693,9 @@ sub gnome_initial_setup {
     # https://bugzilla.gnome.org/show_bug.cgi?id=794825
     @nexts = grep {$_ ne 'software'} @nexts;
 
-    # note: in g-i-s 3.37.91 and later, the first screen has a "Start
-    # Setup" button, not a "Next" button. For code simplicity, we just
-    # have a needle for that button which has the next_button tag
-    assert_screen ["next_button", "auth_required"], $args{timeout};
+    # note: in g-i-s 3.37.91 and later, the first screen in systemwide
+    # mode has a "Start Setup" button, not a "Next" button
+    assert_screen ["next_button", "start_setup", "auth_required"], $args{timeout};
     # workaround auth dialog appearing to change timezone even
     # though timezone screen is disabled
     if (match_has_tag("auth_required")) {

needles/gnome/next_button-startsetup-20200818.json

@@ -10,7 +10,7 @@
   ],
   "properties": [],
   "tags": [
-    "next_button",
+    "start_setup",
     "LANGUAGE-english"
   ]
 }