Fix emoji replacements, make emoji images consistent (#12567)

- Fix emoji not being replaced in issue title change text
- Make the image attributes consistent, add alt, remove align

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

web_src/js/features/emoji.js

@@ -24,7 +24,7 @@ for (const key of emojiKeys) {
 export function emojiHTML(name) {
   let inner;
   if (name === 'gitea') {
-    inner = `<img class="emoji" alt=":${name}:" src="${StaticUrlPrefix}/img/emoji/gitea.png" align="absmiddle">`;
+    inner = `<img alt=":${name}:" src="${StaticUrlPrefix}/img/emoji/gitea.png">`;
   } else {
     inner = emojiString(name);
   }