chore(all): auto-regenerate .pb.go files (googleapis#531)

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#3702

Changes:

chore(longrunning): Operations proto comment cleanup
  Committer: @miraleung
  PiperOrigin-RevId: 357075713
  Source-Link: googleapis/googleapis@c059c46

docs(billing/budgets): Update rules for currency_code in budget_amount.
  PiperOrigin-RevId: 357051517
  Source-Link: googleapis/googleapis@f3a60f6

regen.txt

@@ -1 +1 @@
-f3a60f63c13fb434745ea59b990a82d6ffc803b5
+c059c46957b0eb83078e61b4a5170c3d09ea96e6