Auto Collapse Behaviour - Collapse left panel on window resize (#32964)

* Add functionality to UIStore

- Make it possible to query if the window is currently being resized
- Emit WidthIncreased/WidthDecreased events

* Change resize behaviour of panel

So that the panel does not become smaller when the window is resized.
This is consistent with the old room-list design.

* Introduce a `CollapseHandler` object

This should be used by the collapse behaviours to collapse/expand the
panel. There's a good reason to not have the behaviours depend directly
on the react-resizable-panels API methods: We dont want the collapse/expand
calls to conflict with each other. See the comments in the code for more
information.

* Introduce a base class for collapse behaviour logic

Behaviours should extend this class to describe when the panel should
automatically collapse and expand.

* Add the window resize collapse behaviour

* Create a central file from which to export all behaviours

* Add a class to orchestrate the collapse behaviours

ResizerViewModel will only have a dependency on this class.

* Collapse panel on app start if necessary

For eg, if the app is started with a small window width, the panel should be
collapsed.

* Wire auto collapse code into the viewmodel

* Write jest tests

* Fix e2e tests

* Fix lint error

* Fix e2e test failures

* Expand the panel before taking screenshot

Fixes incorrect narrow screenshots in RTE.spec.ts and CIDER.spec.ts

* Make comments consistent

* Move tests from jest to vitest

* Fix lint errors

* Improve comment

* Remove variable

* Remove mock

* Fix comment formatting

packages/shared-components/src/resize/panel/LeftResizablePanelView.tsx

@@ -66,6 +66,7 @@ export function LeftResizablePanelView({
             defaultSize={defaultSize}
             onResize={vm.onLeftPanelResize}
             panelRef={setPanelRef}
+            groupResizeBehavior="preserve-pixel-size"
         >
             {children}
         </Panel>