chore(infra): Increase PG backups to 30 days (#8433)

These are currently 7. It would be good to have more retention here.

terraform/modules/google-cloud/sql/main.tf

@@ -75,7 +75,7 @@ resource "google_sql_database_instance" "master" {
       point_in_time_recovery_enabled = length(var.database_read_replica_locations) > 0 ? true : var.database_backups_enabled
 
       backup_retention_settings {
-        retained_backups = 7
+        retained_backups = 30
       }
     }