Fix Emoji picker cut off at RHS (#6602)

webapp/sass/components/_emoticons.scss

@@ -103,7 +103,7 @@
 }
 
 .emoji-picker__items {
-    max-height: 262px;
+    max-height: 278px;
     overflow-x: hidden;
     overflow-y: auto;
     padding: 0px 8px 8px 8px;

webapp/sass/layout/_post-right.scss

@@ -148,7 +148,6 @@
 .post-right__scroll {
     -webkit-overflow-scrolling: touch;
     @include flex(1 1 auto);
-    overflow: auto;
     padding-top: 10px;
     position: relative;