Alloydb CRR Promote Secondary Cluster

[modular-magician]

To Promote a Secondary Cluster, perform the following 2 changes in the secondary cluster config.

  1. Modify cluster_type = "PRIMARY"
  2. Remove the entire secondary_config field from the config 

Before

resource "google_alloydb_cluster" "secondary" {
  <required-fields> = <value>
  <other-fields> = <value>

  cluster_type = "SECONDARY"
  secondary_config {
    primary_cluster_name = google_alloydb_cluster.primary.name
  }
}

After

resource "google_alloydb_cluster" "secondary" {
  <required-fields> = <value>
  <other-fields> = <value>

  cluster_type = "PRIMARY"
}

After promotion the secondary cluster becomes an independent primary cluster.

Release Note Template for Downstream PRs (will be copied)

alloydb: added support for promotion for `SECONDARY` `google_alloydb_cluster` resources

Derived from GoogleCloudPlatform/magic-modules#9271

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