Change avatar to use Compound implementation (#11448)

* Move avatar to new compound implementation

* Make space avatars square

* Remove reference to the avatar initial CSS class

* remove references to mx_BaseAvatar_image

* Fixe test suites

* Fix accessbility violations

* Add ConfirmUserActionDialog test

* Fix tests

* Add FacePile test

* Fix items clipping in members list

* Fix user info avatar sizing

* Fix tests

src/autocomplete/UserProvider.tsx

@@ -135,7 +135,7 @@ export default class UserProvider extends AutocompleteProvider {
                     href: makeUserPermalink(user.userId),
                     component: (
                         <PillCompletion title={displayName} description={description}>
-                            <MemberAvatar member={user} width={24} height={24} />
+                            <MemberAvatar member={user} size="24px" />
                         </PillCompletion>
                     ),
                     range: range!,