Add node_group to container cluster node_config

[slevenick]

Test passes in CI & locally with increased quota

Fixes: hashicorp/terraform-provider-google#10629

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)

container: added `node_group` to `node_config` for container clusters and node pools to support sole tenancy

[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, 65 insertions(+))
Terraform Beta: Diff ( 2 files changed, 64 insertions(+))

[modular-magician]

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

Diff report:

Terraform GA: Diff ( 3 files changed, 66 insertions(+))
Terraform Beta: Diff ( 3 files changed, 65 insertions(+))

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccApigeeEnvironmentIamBindingGenerated|TestAccApigeeEnvironmentIamMemberGenerated|TestAccApigeeEnvironmentIamPolicyGenerated|TestAccCloudFunctionsFunction_vpcConnector|TestAccComputeRegionNetworkEndpointGroup_regionNetworkEndpointGroupAppengineExample|TestAccContainerCluster_withSoleTenantGroup|TestAccContainerNodePool_withWorkloadIdentityConfig You can view the result here: https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=223401

[modular-magician]

Tests failed during RECORDING mode: TestAccCloudFunctionsFunction_vpcConnector|TestAccComputeRegionNetworkEndpointGroup_regionNetworkEndpointGroupAppengineExample Please fix these to complete your PR