Correctly make polls and media mutually exclusive (mastodon#10141)

Author: ClearlyClaire

app/services/post_status_service.rb

@@ -95,7 +95,7 @@ def postprocess_status!
   def validate_media!
     return if @options[:media_ids].blank? || !@options[:media_ids].is_a?(Enumerable)
 
-    raise Mastodon::ValidationError, I18n.t('media_attachments.validations.too_many') if @options[:media_ids].size > 4 || @options[:poll_id].present?
+    raise Mastodon::ValidationError, I18n.t('media_attachments.validations.too_many') if @options[:media_ids].size > 4 || @options[:poll].present?
 
     @media = @account.media_attachments.where(status_id: nil).where(id: @options[:media_ids].take(4).map(&:to_i))