PLT-6127/PLT-6135/PLT-6137 Added EmojiPickerOverlay component to better position emoji picker (#6352)

* Cleaned up emoji picker CSS

* Fixed border of emoji picker when reacting to comments in the RHS

* PLT-6135 Made EmojiPicker automatically position itself above/below the [...] menu

* PLT-6135 Changed post textbox emoji picker to use a RootCloseWrapper

* PLT-6135 Changed comment textbox emoji picker to use a RootCloseWrapper

* PLT-6135 Changed RHS post components to use EmojiPickerOverlay

* Removed react-outside-event package

* Fixed merge conflict

* Fixed emoji picker position on posts in RHS

* Removed unused CSS classes

* Fixed not being able to react to posts with emoji picker

webapp/sass/layout/_post-right.scss

@@ -92,6 +92,12 @@
             margin-right: 10px;
             padding: 6px 0;
         }
+
+        .emoji-picker {
+            position: absolute;
+            top: -361px;
+            right: 0px;
+        }
     }
 }
 

webapp/sass/layout/_post.scss

@@ -393,6 +393,12 @@
         }
     }
 
+    .emoji-picker {
+        position: absolute;
+        top: -361px;
+        right: 0px;
+    }
+
     .post-create.scroll {
         .btn-file {
             right: 10px;