Remove block_mouse_down in favor of stop_mouse_events_except_scroll (#30401)

This method was added in #20649 to be an alternative of `occlude` which
allows scroll events. It seems a bit arbitrary to only stop left mouse
downs, so this seems like it's probably an improvement.

Release Notes:

- N/A

crates/repl/src/session.rs

@@ -162,7 +162,7 @@ impl EditorBlock {
 
             div()
                 .id(cx.block_id)
-                .block_mouse_down()
+                .block_mouse_except_scroll()
                 .flex()
                 .items_start()
                 .min_h(text_line_height)