Address review feedback

- Remove {@link} from @deprecated tag (freben feedback)
- Use Object.hasOwn instead of hasOwnProperty
- Use NotImplementedError instead of plain Error
- Add @backstage/errors dependency
- Add tests for withApis in core-compat-api

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

yarn.lock

@@ -3580,6 +3580,7 @@ __metadata:
     "@backstage/cli": "workspace:^"
     "@backstage/core-app-api": "workspace:^"
     "@backstage/core-plugin-api": "workspace:^"
+    "@backstage/errors": "workspace:^"
     "@backstage/frontend-app-api": "workspace:^"
     "@backstage/frontend-plugin-api": "workspace:^"
     "@backstage/frontend-test-utils": "workspace:^"