Add border to review panel (#22407)

GitOrigin-RevId: 8b5f683500056c31055597fd85dcb492960a5f6f

services/web/frontend/stylesheets/app/editor/review-panel-new.less

@@ -11,7 +11,7 @@
     z-index: 6;
     flex-shrink: 0;
     background-color: @neutral-10;
-    border-left: solid 0 @neutral-20;
+    border-left: 1px solid @neutral-20;
     color: @content-primary;
     font-family: @font-family-base;
     line-height: @line-height-base;

services/web/frontend/stylesheets/bootstrap-5/pages/editor/review-panel-new.scss

@@ -11,7 +11,7 @@
     z-index: 6;
     flex-shrink: 0;
     background-color: var(--neutral-10);
-    border-left: solid 0 var(--neutral-20);
+    border-left: 1px solid var(--border-divider);
     color: var(--content-primary);
     font-family: $font-family-base;
     line-height: $line-height-base;