Promote Confidential VM to GA

[upodroid]

Fixes: hashicorp/terraform-provider-google#7983

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

compute: promoted `confidential_instance_config` field in `google_compute_instance` and `google_compute_instance_template` to GA

[modular-magician]

Hello! I am a robot who works on Magic Modules PRs.

I have detected that you are a community contributor, so your PR will be assigned to someone with a commit-bit on this repo for initial review.

Thanks for your contribution! A human will be with you soon.

@ScottSuarez, please review this PR or find an appropriate assignee.

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 7 files changed, 234 insertions(+), 36 deletions(-))
Terraform Beta: Diff ( 5 files changed, 7 insertions(+), 11 deletions(-))
TF Conversion: Diff ( 1 file changed, 22 insertions(+))

[ScottSuarez]

/gcbrun

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=164685"

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 7 files changed, 234 insertions(+), 36 deletions(-))
Terraform Beta: Diff ( 5 files changed, 7 insertions(+), 11 deletions(-))
TF Conversion: Diff ( 1 file changed, 22 insertions(+))

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccDataSourceStorageBucketObjectContent_Basic|TestAccActiveDirectoryDomainTrust_activeDirectoryDomainTrustBasicExample|TestAccBigtableAppProfile_bigtableAppProfileSingleclusterExample|TestAccBigtableAppProfile_bigtableAppProfileMulticlusterExample|TestAccContainerCluster_withConfidentialNodes|TestAccContainerCluster_withPrivateClusterConfigMissingCidrBlock|TestAccContainerCluster_withIPv4Error|TestAccDataprocJob_Spark You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=164690"