Update Topology Service client gem (drop Bucket in favor of Claim)

What does this MR do?

Re-vendors the Topology Service Ruby client gem (vendor/gems/gitlab-topology-service-client) by running scripts/update-topology-service-gem.sh, pointed at the Topology Service branch swh/deprecate-bucket-for-claim (REF=swh/deprecate-bucket-for-claim).

This picks up the removal of the Bucket message from the ClaimService proto in favor of Claim (topology-service!551), along with other client changes merged since the previously pinned revision (ClassifyPages RPC, pages_address on CellInfo).

Revision pin bumped from cd733cdf → a9875d34.

Why is this needed?

Follow-up to topology-service!551. Rails vendors the client by SHA, so once that MR merges this regeneration is required for the Rails app to pick up the Bucket → Claim change. Verified nothing in gitlab-org/gitlab still references the dropped Bucket classes.

Notes

• Draft until topology-service!551 merges. The gem was regenerated against the branch; before merging this MR, re-run the script against main so the pinned SHA points at the merged commit rather than the branch HEAD.

Related: gitlab-org/cells/topology-service!551 (merged)