chore(librarian): remove incomplete entry in config.yaml (#16768)

#16549 removed
`release_blocked` for `google-cloud-firestore`. The `generated_blocked`
was not removed however since `id: google-cloud-firestore` was removed
in the PR, the `generated_blocked` remained in the config.yaml as an
incorrect entry.

There is already an entry for `google-cloud-firestore` with
`generate_blocked` here:


https://github.com/googleapis/google-cloud-python/blob/f03d376efb45aa6eb44d0396b600b0683055e83b/.librarian/config.yaml#L267-L268

Author: parthea

.librarian/config.yaml

@@ -15,7 +15,6 @@ libraries:
   - generate_blocked: true
     id: bigframes
     release_blocked: true
-  - generate_blocked: true
   - generate_blocked: true
     id: google-cloud-dialogflow
   - generate_blocked: true