Avoid creating occlusions for editor blocks, since these block mouse wheel events (#20649)

Just block mouse down events, and in the case of the inline assist
prompt, set the default cursor.

Release Notes:

- N/A

Co-authored-by: Richard <richard@zed.dev>

crates/repl/src/session.rs

@@ -163,7 +163,7 @@ impl EditorBlock {
 
             div()
                 .id(cx.block_id)
-                .occlude()
+                .block_mouse_down()
                 .flex()
                 .items_start()
                 .min_h(text_line_height)