Add support for custom emojis in poll options (#10322)

* Backend changes for custom emoji support in poll options

* Serialize poll emojis in REST API

* Render custom emojis in poll options

* Render custom emoji in poll options on public pages

app/views/stream_entries/_poll.html.haml

@@ -10,11 +10,11 @@
 
           %label.poll__text><
             %span.poll__number= percent.round
-            = option.title
+            = Formatter.instance.format_poll_option(status, option, autoplay: autoplay)
         - else
           %label.poll__text><
             %span.poll__input{ class: poll.multiple? ? 'checkbox' : nil}><
-            = option.title
+            = Formatter.instance.format_poll_option(status, option, autoplay: autoplay)
   .poll__footer
     - unless show_results
       %button.button.button-secondary{ disabled: true }