FEATURE: my threads page (#24771)

This commit adds a new "My threads" link in sidebar and drawer. This link will open the "/chat/threads" page which contains all threads where the current user is a member. It's ordered by activity (unread and then last message created).

Moreover, the threads list of a channel page is now showing every threads of a channel, and not just the ones where you are a member.

plugins/chat/spec/fabricators/chat_fabricator.rb

@@ -220,12 +220,16 @@ Fabricator(:chat_thread, class_name: "Chat::Thread") do
     thread.add(thread.original_message_user)
 
     if transients[:with_replies]
-      Fabricate.times(
-        transients[:with_replies],
-        :chat_message,
-        thread: thread,
-        use_service: transients[:use_service],
-      )
+      Fabricate
+        .times(
+          transients[:with_replies],
+          :chat_message,
+          thread: thread,
+          use_service: transients[:use_service],
+        )
+        .each { |message| thread.add(message.user) }
+
+      thread.update!(replies_count: transients[:with_replies])
     end
   end
 end