Fix visibility toggle for maximized Space Views (#2806)

### What

Fixes #2575
* #2575


https://github.com/rerun-io/rerun/assets/1220815/524968b5-483b-4f6b-9c2f-00a65e5f8584



### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested [demo.rerun.io](https://demo.rerun.io/pr/2806) (if
applicable)

- [PR Build Summary](https://build.rerun.io/pr/2806)
- [Docs
preview](https://rerun.io/preview/pr%3Aandreas%2Ffix-maximized-view-visiblity-change/docs)
- [Examples
preview](https://rerun.io/preview/pr%3Aandreas%2Ffix-maximized-view-visiblity-change/examples)

crates/re_viewport/src/viewport.rs

@@ -103,6 +103,10 @@ impl<'a, 'b> Viewport<'a, 'b> {
         if let Some(space_view_id) = blueprint.maximized {
             if !blueprint.space_views.contains_key(&space_view_id) {
                 blueprint.maximized = None; // protect against bad deserialized data
+            } else if let Some(tile_id) = blueprint.tree.tiles.find_pane(&space_view_id) {
+                if !blueprint.tree.tiles.is_visible(tile_id) {
+                    blueprint.maximized = None; // Automatically de-maximize views that aren't visible anymore.
+                }
             }
         }