Inspector v2: Scene Explorer expand/collapse all (#17024)

This change brings expand/collapse all to scene explorer.
- Previously there was a single useMemo that traversed the expanded part
of the scene and created TreeItemData only for the expanded nodes. I've
broken this out now into two different useMemos. The first one creates
TreeItemData for *all* entities, and the second one filters down those
TreeItemData into only those that are expanded/visible. I'd already been
thinking about reworking it like this for other reasons as it simplifies
a lot of things. As part of this, I was able to simplify the interface a
scene explorer section in that it no longer needs to provide a predicate
or a function to get the parent (which can now be inferred from the
internal TreeItemData tree structure).
- Removed the unnecessary type param from all the scene explorer command
interfaces and components. This was needed when a command instance was
not tied to a specific entity instance, but now they are 1:1, so there
is no need to pass an entity into a command instance (it holds it
internally). This is just cleanup that I missed in previous changes.
- Expand/collapse all can be triggered in a similar way as inspector v1
by holding down shift (or ctrl) when clicking the expand/collapse button
on a tree node. I also added explicit context menus to help make it more
discoverable. I did not make the context menus extensible in this PR,
but may in a future change if we think it makes sense to be able to add
in more items to the context menu dynamically.
- Also updated to the virtualizer that is no longer in preview state. It
is part of the fluent contrib package family, which is analogous to
Babylon's Addons package.

<img width="374" height="395" alt="image"
src="https://github.com/user-attachments/assets/386244a1-f521-47e1-beee-d4cea7d32426"
/>

Author: ryantrem

package-lock.json

@@ -22,6 +22,7 @@
         "@dev/loaders": "1.0.0",
         "@dev/materials": "^1.0.0",
         "@dev/serializers": "1.0.0",
+        "@fluentui-contrib/react-virtualizer": "^0.1.0",
         "@fluentui/react-components": "^9.62.0",
         "@fluentui/react-icons": "^2.0.271",
         "@pmmmwh/react-refresh-webpack-plugin": "^0.6.0",