Send empty privateVisibilityConfig network array

[modular-magician]

fixes #6973

The api only removes the privateVisibilityConfig block when sending an empty networks array like so:

  "privateVisibilityConfig": {
    "networks": []
  }

Added a custom expander to do this. Using a custom expander on the parent field removed the expanders for the subfields, so I included the subfield expanders in the template. This makes the custom expander looks excessive, but generates small downstream diffs.

Release Note Template for Downstream PRs (will be copied)

dns: fixed an issue where `google_dns_managed_zone` would not remove `private_visibility_config` on updates

Derived from GoogleCloudPlatform/magic-modules#3865

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. If you feel I made an error 🤖 🙉 , please reach out to my human friends 👉 [email protected]. Thanks!