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

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.
- Approve and submit this PR if you believe it's ready to ship. That will prompt
genbot to assign reviewers to the google-cloud-go PR.

Corresponding google-cloud-go PR: googleapis/google-cloud-go#4423

Changes:

chore: regenerate API index

  Source-Link: googleapis/googleapis@f81e4aa

chore: publish Storage v2 API artifacts
  PiperOrigin-RevId: 384339914
  Source-Link: googleapis/googleapis@cdea5d8

feat(bigquery/connection): add cloud spanner connection support
  PiperOrigin-RevId: 384325792
  Source-Link: googleapis/googleapis@eba5492

feat: Update the example for report v2 integration.
  For more information, see https://cloud.google.com/service-infrastructure/docs/service-control/reference/rest/v2/services/report.

  PiperOrigin-RevId: 384308323
  Source-Link: googleapis/googleapis@c61a01d

chore: regenerate API index

  Source-Link: googleapis/googleapis@acb4f89

feat: Update the example for report v2 integration.
  For more information, see https://cloud.google.com/service-infrastructure/docs/service-control/reference/rest/v2/services/report.

  PiperOrigin-RevId: 384282796
  Source-Link: googleapis/googleapis@bae1011