Add CSS cascade layers for Compound, shared components, and app/web styles (#33302)

* Layer Compound and shared component CSS

* Layer app theme CSS

* Remove !important flags from ActionBarView

* Remove unnecessary !important statements from shared components

* Avoid dead code errors for *.pcss just because layer is specified after @import url

* Remove unnecessary !important styling

* Override Banner defaults in RoomStatusBarView

* Updated snaps

* Updated snaps

* Fix styling of media body in app/web

* Fix styling for Compound anchors

* Fix styling issues in app/web

* More styling fixes

* Fix a problem extracting css for HTMLExport

* Revert changes

* Fix for theme styling

* Add test to improve coverage

* Prettier

* Fix styling issues

* Add data-kind attribute to avoid global styling override

* Update screenshot that now is correct

* Revert data-kind attribute

* Handle LinkPreview styling in .pcss

* Fix flaky test: Avoid racing the lazy-loaded ManageEventIndexDialog

* Take care of review comments

* Updated snaps

* Updated snaps again after merge

* Remove !important from RoomStatusBar

apps/web/src/components/views/messages/TextualBodyFactory.tsx

@@ -210,7 +210,7 @@ export function TextualBodyFactory(props: Readonly<IBodyProps>): JSX.Element {
             vm={textualBodyVm}
             body={<EventContentBodyView vm={eventContentBodyVm} as={willHaveWrapper ? "span" : "div"} />}
             bodyRef={contentRef}
-            urlPreviews={<UrlPreviewGroupView vm={urlPreviewVm} />}
+            urlPreviews={<UrlPreviewGroupView vm={urlPreviewVm} className="mx_TextualBody_urlPreviews" />}
             className={getTextualBodyClassName(content.msgtype as MsgType | undefined)}
         />
     );