backend-plugin-api: deprecate service factories with callback form

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/events-node/api-report.md

@@ -4,7 +4,7 @@
 
 ```ts
 import { LoggerService } from '@backstage/backend-plugin-api';
-import { ServiceFactory } from '@backstage/backend-plugin-api';
+import { ServiceFactoryCompat } from '@backstage/backend-plugin-api';
 import { ServiceRef } from '@backstage/backend-plugin-api';
 
 // @public
@@ -63,9 +63,10 @@ export interface EventsService {
 export type EventsServiceEventHandler = (params: EventParams) => Promise<void>;
 
 // @public (undocumented)
-export const eventsServiceFactory: () => ServiceFactory<
+export const eventsServiceFactory: ServiceFactoryCompat<
   EventsService,
-  'plugin'
+  'plugin',
+  undefined
 >;
 
 // @public