patch 9.1.1489: terminal: no visual highlight of empty cols with empty 'listchars'

Problem:  terminal: no visual highlight of empty cols when 'listchars'
          is empty (Yousef Mohammed)
Solution: reset wlv.win_attr when column is zero and we are drawing a
          terminal buffer

fixes: #17559
closes: #17618

Co-authored-by: Hirohito Higashi <h.east.727@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 8e6849a..e912070 100644
--- a/src/version.c
+++ b/src/version.c
@@ -720,6 +720,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1489,
+/**/
     1488,
 /**/
     1487,