Use region from provider as default location in Artifact Registry

[modular-magician]

Fixes hashicorp/terraform-provider-google#10436, hashicorp/terraform-provider-google#13585, hashicorp/terraform-provider-google#13294

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Release Note Template for Downstream PRs (will be copied)

artifactregistry: fixed new repositories ignoring the provider region if location is unset. 

Derived from GoogleCloudPlatform/magic-modules#7497