fix: permadiff issue when docker_repository field is not specified

relates to GoogleCloudPlatform/cloud-foundation-fabric#1987
When docker repository is not specified by default docker repository`projects/PROJECT_ID/locations/REGION/repositories/gcf-artifacts` is used.In such a case, terraform plan always generates a difference for `docker_repository`field as the module passes null value but the tfstate file has the above specifieddefault value. This fix allows one to prevent unnecessary infrastructure change.

mmv1/products/cloudfunctions2/Function.yaml

@@ -422,6 +422,7 @@ properties:
         name: 'dockerRepository'
         description: |
           User managed repository created in Artifact Registry optionally with a customer managed encryption key.
+        default_from_api: true
   - !ruby/object:Api::Type::NestedObject
     name: 'serviceConfig'
     description: 'Describes the Service being deployed.'