Use the server setting to get the max number of poll options in UI (#29490)

app/javascript/mastodon/actions/compose.js

@@ -786,11 +786,12 @@ export function addPollOption(title) {
   };
 }
 
-export function changePollOption(index, title) {
+export function changePollOption(index, title, maxOptions) {
   return {
     type: COMPOSE_POLL_OPTION_CHANGE,
     index,
     title,
+    maxOptions,
   };
 }