fix: update connection metadata (#456)

Author: q2w

modules/instance_template/metadata.yaml

@@ -269,7 +269,7 @@ spec:
               source: github.com/terraform-google-modules/terraform-google-memorystore
               version: ">= 12.0"
             spec:
-              outputExpr: "{\"REDIS_HOST\": host, \"REDIS_PORT\": port}"
+              outputExpr: "{\"REDIS_HOST\": host, \"REDIS_PORT\": env_vars.REDIS_PORT}"
           - source:
               source: github.com/terraform-google-modules/terraform-google-sql-db//modules/postgresql
               version: ">= 23.0"