patch 9.1.1470: use-after-free with popup callback on error

Problem:  use-after-free with popup callback on error
          (Brian Carbone, lifepillar)
Solution: check if the popup window is valid before accessing it

fixes: #17558
closes: #17565

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/version.c

@@ -709,6 +709,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1470,
 /**/
     1469,
 /**/