Add aws_rdsdata_query datasource

[psantus]

Description

Adds support for RDS Data Query

data "aws_rdsdata_query" "test" {
  depends_on   = [aws_rds_cluster_instance.test]
  resource_arn = aws_rds_cluster.test.arn
  secret_arn   = aws_secretsmanager_secret.test.arn
  sql          = "SELECT :param1 as test_column"
  
  parameters {
    name  = "param1"
    value = "test_value"
  }
}

Relations

Closes #40901
Refs #44472

On top of #44629 ( Add RDS Data Service) - To REVIEWER only the last commit is specific to this branch/PR.

References

https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/data-api.html
https://docs.aws.amazon.com/rdsdataservice/latest/APIReference/API_ExecuteStatement.html

Output from Acceptance Testing

% TF_ACC=1 go test ./internal/service/rdsdata/... -v -run="TestAccRDSDataQueryDataSource" -timeout=30m

2025/10/13 00:20:23 Creating Terraform AWS Provider (SDKv2-style)...
2025/10/13 00:20:23 Initializing Terraform AWS Provider (SDKv2-style)...
=== RUN   TestAccRDSDataQueryDataSource_basic
=== PAUSE TestAccRDSDataQueryDataSource_basic
=== RUN   TestAccRDSDataQueryDataSource_withParameters
=== PAUSE TestAccRDSDataQueryDataSource_withParameters
=== CONT  TestAccRDSDataQueryDataSource_basic
=== CONT  TestAccRDSDataQueryDataSource_withParameters
--- PASS: TestAccRDSDataQueryDataSource_basic (828.47s)
--- PASS: TestAccRDSDataQueryDataSource_withParameters (1219.22s)
PASS
ok      github.com/hashicorp/terraform-provider-aws/internal/service/rdsdata    1224.054s

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