Add export FHIR store to GCS test. (#1804)
Add export FHIR store to GCS test. (#1804)

* Add export FHIR store to GCS test.

* Update import/export tests

GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples,GoogleCloudPlatform/python-docs-samples