Minor Ui bug fixes (#6295)

* PLT-6435 - Adjusting tooltip for add-channel-btn

* PLT-6404 - Fixing emoji reaction button on hover

webapp/sass/layout/_post.scss

@@ -646,6 +646,7 @@
         .comment-icon__container,
         .post__reply,
         .post__remove,
+        .reacticon__container,
         .permalink-icon {
             visibility: visible;
         }