chore(all): auto-regenerate .pb.go files (googleapis#715)

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#5082

Changes:

chore: generate java files for source_context.proto
  PiperOrigin-RevId: 407625510
  Source-Link: googleapis/googleapis@25c7592

chore: regenerate API index

  Source-Link: googleapis/googleapis@7ab35b4

feat(dialogflow/cx): added support for comparing between versions docs: clarified security settings API reference
  PiperOrigin-RevId: 407624272
  Source-Link: googleapis/googleapis@eb773f2

docs(channel): clarified usage of entitlement parameters
  PiperOrigin-RevId: 407463572
  Source-Link: googleapis/googleapis@e4c5b78

chore: regenerate API index

  Source-Link: googleapis/googleapis@c7e4a61

feat(osconfig): OSConfig: add OS policy assignment rpcs
  Committer: @adjackura
  PiperOrigin-RevId: 407422484
  Source-Link: googleapis/googleapis@c11bc3e

chore: regenerate API index

  Source-Link: googleapis/googleapis@204a776

feat(googleads): v9 of Google Ads API
  Committer: @aohren
  PiperOrigin-RevId: 407394604
  Source-Link: googleapis/googleapis@19b6b89

chore: regenerate API index

  Source-Link: googleapis/googleapis@0801ed6

fix(security/privateca): repair service config to enable mixins
  PiperOrigin-RevId: 407356040
  Source-Link: googleapis/googleapis@171e2c7

chore(ruby): Corrected build rules for Ruby wrappers for the monitoring and workflows APIs
  PiperOrigin-RevId: 407259483
  Source-Link: googleapis/googleapis@0c2e454