fix: Address missing Bazel dependency.
fix: Address missing Bazel dependency.

Bazel builds stopped working in 06ec6d5 because
the google/longrunning/operations.proto file took
an import from google/api/client.proto, but that
import was not added to BUILD.bazel.

Committer: da39a3ee5e6b4b0d3255bfef95601890afd80709@lukesneeringer
PiperOrigin-RevId: 289446074

googleapis/googleapis,googleapis/googleapis