fix: backoffice link in plain (#6609)

Author: psincraian

server/polar/integrations/plain/service.py

@@ -581,11 +581,13 @@ async def create_appeal_review_thread(
                                             ],
                                         )
                                     ),
-                                    # Admin Dashboard Link
+                                    # Backoffice Link
                                     ComponentContainerContentInput(
                                         component_link_button=ComponentLinkButtonInput(
-                                            link_button_url=f"{settings.FRONTEND_BASE_URL}/backoffice/organizations/{organization.id}",
-                                            link_button_label="View in Admin Dashboard",
+                                            link_button_url=settings.generate_external_url(
+                                                f"/backoffice/organizations/{organization.id}"
+                                            ),
+                                            link_button_label="View in Backoffice",
                                         )
                                     ),
                                 ]