patch 8.2.2428: FocusGained does not work when 'ttymouse' is empty

Problem:    FocusGained does not work when 'ttymouse' is empty.
Solution:   Don't use the short mouse code if there is a longer matching code.
            (closes #7755)  Add a test.
diff --git a/src/version.c b/src/version.c
index 98f01dd..f7e267f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2428,
+/**/
     2427,
 /**/
     2426,