patch 8.2.2352: if focus lost/gained is received twice code is not ignored

Problem:    If the focus lost/gained escape sequence is received twice it is
            not ignored. (Christ van Willigen)
Solution:   Adjust the logic to ignore the escape code.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2352,
 /**/
     2351,
 /**/