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

res/css/structures/_SpaceHierarchy.pcss

@@ -108,12 +108,6 @@ limitations under the License.
         }
     }
 
-    .mx_SpaceHierarchy_subspace {
-        .mx_BaseAvatar_image {
-            border-radius: 8px;
-        }
-    }
-
     .mx_SpaceHierarchy_subspace_toggle {
         position: absolute;
         left: -1px;