Fix jumping views

Fixes #2490.

To be honest I'm not sure why this fixes the issue.

I observed that I could only make the view jump if I resized it to the
smallest possible size first. Then I had a suspicion that we were
accidentally factoring in the title and border sizes into the view size
when it uses CSD. So I changed that and it appears to have fixed the
jumping issue.

I guess when we factor the title and borders in, we send a configure to
the surface with a size smaller than the minimum, and it comes back with
a surface at the minimum size. We interpret this as an unexpected
resize, and this somehow makes it jump.

sway/tree/view.c

@@ -236,7 +236,12 @@ void view_autoconfigure(struct sway_view *view) {
 		view->border_top = false;
 	}
 
-	switch (view->border) {
+	enum sway_container_border border = view->border;
+	if (view->using_csd) {
+		border = B_NONE;
+	}
+
+	switch (border) {
 	case B_NONE:
 		x = con->x;
 		y = con->y + y_offset;