Fix and document id format for google_kms_crypto_key_version.

[rileykarson]

Fixes hashicorp/terraform-provider-google#6538

Release Note Template for Downstream PRs (will be copied)

kms: fixed the `id` value in the `google_kms_crypto_key_version` datasource to include an `/v1` part following `//cloudkms.googleapis.com/`, making it useful for interpolation into Binary Authorization.

[modular-magician]

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

Diff report:

Terraform GA: Diff ( 2 files changed, 3 insertions(+), 1 deletion(-))
Terraform Beta: Diff ( 2 files changed, 3 insertions(+), 1 deletion(-))

[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=119272"