Fixed emoji to resize when used in headers (#4718)

webapp/sass/components/_emoticons.scss

@@ -5,10 +5,9 @@
     background-position: 50% 50%;
     background-size: contain;
     display: inline-block;
-    font-size: 19px;
+    height: 1.3em;
-    height: 1em;
     vertical-align: text-top;
-    width: 1em;
+    width: 1.3em;
 }
 
 .emoticon-suggestion {