Rework Upload internals to use MVVM (#33307)

* Initial reword of upload to MVVM.

* Update tests

* More incremental improvements

* Refactor tests to use helper method for composer uploads.

* Add drag and drop tests

* lint

* Add commentary

* fixup test

* More precise selector

* Retarget uploads

* lint

* fixup

* one more type

* update snap

* Fixup composerUploadFiles

* fix import

* lint

* Copy and paste fixes too

* Add tests for pasting

* Add tests for pasting files.

* Remove redundant fn

* rm comment

* tidy up

* Test cleanup

* More clean up

* another fix

* Use condensed version

* Cleanup tests

* more cleaning

* last bity

* s/throw Error/throw new Error/

apps/web/test/unit-tests/components/views/rooms/MessageComposer-test.tsx

@@ -36,6 +36,10 @@ import UIStore, { UI_EVENTS } from "../../../../../src/stores/UIStore";
 import { Action } from "../../../../../src/dispatcher/actions";
 import { ScopedRoomContextProvider } from "../../../../../src/contexts/ScopedRoomContext.tsx";
 import type { RoomContextType } from "../../../../../src/contexts/RoomContext.ts";
+import {
+    RoomUploadContext,
+    type RoomUploadViewModel,
+} from "../../../../../src/viewmodels/room/RoomUploadViewModel.tsx";
 
 const openStickerPicker = async (): Promise<void> => {
     await userEvent.click(screen.getByLabelText("More options"));
@@ -469,7 +473,9 @@ function wrapAndRender(
     const getRawComponent = (props = {}, context = roomContext, client = mockClient) => (
         <MatrixClientContext.Provider value={client}>
             <ScopedRoomContextProvider {...context}>
-                <MessageComposer {...defaultProps} {...props} />
+                <RoomUploadContext.Provider value={{} as RoomUploadViewModel}>
+                    <MessageComposer {...defaultProps} {...props} />
+                </RoomUploadContext.Provider>
             </ScopedRoomContextProvider>
         </MatrixClientContext.Provider>
     );