Property Search: Add "search match" theme color

We will use a highlight on panel headers to convey that they have
a search match, so this commit initializes the theme color for the
properties editor.

Differential Revision: https://developer.blender.org/D8854

source/blender/blenloader/intern/versioning_userdef.c

@@ -236,6 +236,8 @@ static void do_versions_theme(const UserDef *userdef, bTheme *btheme)
    */
   {
     /* Keep this block, even when empty. */
+
+    FROM_DEFAULT_V4_UCHAR(space_properties.match);
   }
 
 #undef FROM_DEFAULT_V4_UCHAR