Display reply field if resolved discussion has no replies (EE-port)

app/assets/javascripts/notes/components/noteable_discussion.vue

@@ -428,7 +428,7 @@ Please check your network connection and try again.`;
                 :draft="draftForDiscussion(discussion.reply_id)"
               />
               <div
-                v-else-if="!isRepliesCollapsed"
+                v-else-if="!isRepliesCollapsed || !hasReplies"
                 :class="{ 'is-replying': isReplying }"
                 class="discussion-reply-holder"
               >

changelogs/unreleased/winh-resolved-discussions-reply-field.yml

+---
+title: Display reply field if resolved discussion has no replies
+merge_request: 23801
+author:
+type: fixed

spec/support/features/discussion_comments_shared_example.rb

@@ -178,6 +178,16 @@ shared_examples 'discussion comments' do |resource_name|
           let(:note_id) { find("#{comments_selector} .note:first-child", match: :first)['data-note-id'] }
           let(:reply_id) { find("#{comments_selector} .note:last-child", match: :first)['data-note-id'] }
 
+          it 'can be replied to after resolving' do
+            click_button "Resolve discussion"
+            wait_for_requests
+
+            refresh
+            wait_for_requests
+
+            submit_reply('to reply or not reply')
+          end
+
           it 'shows resolved discussion when toggled' do
             submit_reply('a')