Fix regression around FacePile with overflow (#11527)

* Work around compound-web AvatarStack not applying overlap to non-Avatars

* Fix FacePile overflow tile not being layed out correctly

res/css/views/elements/_FacePile.pcss

@@ -20,6 +20,7 @@ limitations under the License.
     width: 30px;
     height: 30px;
     background-color: $spacePanel-bg-color;
+    display: inline-block;
 
     &::before {
         content: "";