patch 8.2.0235: draw error when an empty group is removed from 'statusline'

Problem:    Draw error when an empty group is removed from 'statusline'.
Solution:   Do not use highlighting from a removed group.
diff --git a/src/buffer.c b/src/buffer.c
index 7ff8097..25620af 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -4216,6 +4216,10 @@
 		{
 		    p = t;
 		    l = 0;
+		    // do not use the highlighting from the removed group
+		    for (n = groupitem[groupdepth] + 1; n < curitem; n++)
+			if (item[n].type == Highlight)
+			    item[n].type = Empty;
 		}
 	    }
 	    if (l > item[groupitem[groupdepth]].maxwid)