Fix up `watch` alias lookup in Firefox

app/assets/javascripts/awards_handler.js

@@ -444,7 +444,7 @@ AwardsHandler.prototype.scrollToAwards = function scrollToAwards() {
 };
 
 AwardsHandler.prototype.normalizeEmojiName = function normalizeEmojiName(emoji) {
-  return this.aliases[emoji] || emoji;
+  return Object.prototype.hasOwnProperty.call(this.aliases, emoji) ? this.aliases[emoji] : emoji;
 };
 
 AwardsHandler

app/assets/javascripts/behaviors/gl_emoji.js

@@ -16,7 +16,8 @@ const glEmojiTagDefaults = {
 };
 function glEmojiTag(inputName, options) {
   const opts = Object.assign({}, glEmojiTagDefaults, options);
-  const name = emojiAliases[inputName] || inputName;
+  const name = Object.prototype.hasOwnProperty.call(emojiAliases, inputName) ?
+    emojiAliases[inputName] : inputName;
   const emojiInfo = emojiMap[name];
   const fallbackImageSrc = `${gon.relative_url_root || ''}/assets/emoji/${name}-${emojiInfo.digest}.png`;
   const fallbackSpriteClass = `emoji-${name}`;