Try hiding cursor in middle right of screen on desktops

os-autoinst is set so that if you once manually set the cursor
somewhere, all subsequent calls to `assert_and_click` will return
the cursor to the last manually-set position (if you never set
the cursor anywhere manually, it uses the `mouse_hide` location).
The mouse_hide location is no good for modern desktops as they
use hot corners in various ways, so for the desktop tests, early
in login, we set the mouse to 300/800, which we hope is a kind
of neutral location that doesn't interfere with matches of the
desktop_background needles (which I usually put towards the
right of the screen).

Unfortunately, KDE can show fairly big previews of active windows
down there, and hovering over one causes that window to be
displayed and all others to be hidden. Which rather breaks the
desktop browser test, when we have the Welcome Center popping up
on boot.

We already moved the mouse set point from 300/200 a few years
back because of a *different* awkward interaction with the browser
test, so we can't go back there. Let's try 1023/384 instead -
that's all the way on the right hand side of the screen, but half
way down, not in either corner. I really hope this doesn't cause
problems for any tests cos I don't know where else to stick the
damn thing if this doesn't work.

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

tests/_graphical_wait_login.pm

@@ -99,8 +99,9 @@ sub run {
         desktop_vt;
     }
 
-    # Move the mouse somewhere it won't highlight the match areas
-    mouse_set(300, 800);
+    # Move the mouse somewhere it won't highlight the match areas and
+    # hopefully won't negatively interact with anything else later
+    mouse_set(1023, 384);
     # KDE can take ages to start up
     check_desktop(timeout => 120);
 }