patch 8.2.4626: Visual area not updated when removing sign in Visual mode

Problem:    Visual area not fully updated when removing sign in Visual mode
            while scrolling.
Solution:   Adjust check for topline. (closes #10017)
diff --git a/src/drawscreen.c b/src/drawscreen.c
index a902397..12eed8c 100644
--- a/src/drawscreen.c
+++ b/src/drawscreen.c
@@ -1730,7 +1730,7 @@
 	if (mod_top != 0
 		&& wp->w_topline == mod_top
 		&& (!wp->w_lines[0].wl_valid
-		    || wp->w_topline <= wp->w_lines[0].wl_lnum))
+		    || wp->w_topline == wp->w_lines[0].wl_lnum))
 	{
 	    // w_topline is the first changed line and window is not scrolled,
 	    // the scrolling from changed lines will be done further down.