chore(all): auto-regenerate .pb.go files (googleapis#526)

This is an auto-generated regeneration of the .pb.go files by
cloud.google.com/go/internal/gapicgen. Once this PR is submitted, genbot will
update the corresponding PR to depend on the newer version of go-genproto, and
assign reviewers. Whilst this or any regen PR is open in go-genproto, genbot
will not create any more regeneration PRs. If all regen PRs are closed,
gapicgen will create a new set of regeneration PRs once per night.

If you have been assigned to review this PR, please:

- Ensure that CI is passing. If it's failing, it requires your manual attention.
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genbot to assign reviewers to the google-cloud-go PR.

Corresponding google-cloud-go PR: googleapis/google-cloud-go#3661

Changes:

chore: remove unused package option from Bazel build in aiplatform, speakerid
  Committer: @miraleung
  PiperOrigin-RevId: 355238153
  Source-Link: googleapis/googleapis@acdf818

feat: Add `ErrorReason` enum from `google.api.error_reason` for Google API and minor proto updates.
  PiperOrigin-RevId: 355218181
  Source-Link: googleapis/googleapis@2f8d204

feat(channel): Add Pub/Sub endpoints for Cloud Channel API.
  PiperOrigin-RevId: 355059873
  Source-Link: googleapis/googleapis@6ef9eae