Centre loading indicator when review panel is open

services/web/public/stylesheets/app/editor/review-panel.less

@@ -117,6 +117,12 @@
 	z-index: 6;
 }
 
+.loading-panel {
+	.rp-size-expanded & {
+		right: @review-panel-width;
+	}
+}
+
 .review-panel-toolbar {
 	display: none;
 	.rp-size-expanded & {