chore(all): auto-regenerate .pb.go files (#857)

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#6337

Changes:

feat(bigquery/migration): Add Presto dialect to bigquerymigration v2 client library
  PiperOrigin-RevId: 460797158
  Source-Link: googleapis/googleapis@46f2598

chore: regenerate API index

  Source-Link: googleapis/googleapis@52cae2e

feat: added support for BatchCreateTasks preview
  PiperOrigin-RevId: 460776984
  Source-Link: googleapis/googleapis@c501985

chore: regenerate API index

  Source-Link: googleapis/googleapis@d87a170

feat: publish cloud networksecurity v1
  PiperOrigin-RevId: 460770654
  Source-Link: googleapis/googleapis@e7edbb9