Merge branch '10364-dismissal-reason-any-comment-CE' into 'master'

CE backport for Dismissal Reasons

See merge request gitlab-org/gitlab-ce!29422

app/assets/stylesheets/framework/modal.scss

@@ -63,6 +63,10 @@
     margin-left: $grid-size;
   }
 
+  .btn-group .btn + .btn {
+    margin-left: -1px;
+  }
+
   @include media-breakpoint-down(xs) {
     flex-direction: column;
 
@@ -72,6 +76,11 @@
       margin-left: 0;
       margin-top: $grid-size;
     }
+
+    .btn-group .btn + .btn {
+      margin-left: -1px;
+      margin-top: 0;
+    }
   }
 }