Registry tool: ensure yaml archive storage works across all tests

[theganyo]

Follow-up from an earlier YAML storage PR:

--- FAIL: TestConformance (0.19s)
    --- FAIL: TestConformance/normal_case (0.05s)
        conformance_test.go:465: Failed getting artifact contents projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest: rpc error: code = NotFound desc = "projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest" not found in database
    --- FAIL: TestConformance/default_case (0.04s)
        conformance_test.go:465: Failed getting artifact contents projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-default: rpc error: code = NotFound desc = "projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-default" not found in database
    --- FAIL: TestConformance/multiple_severity (0.03s)
        conformance_test.go:465: Failed getting artifact contents projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-severity: rpc error: code = NotFound desc = "projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-severity" not found in database
    --- FAIL: TestConformance/multiple_state (0.04s)
        conformance_test.go:465: Failed getting artifact contents projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-state: rpc error: code = NotFound desc = "projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-state" not found in database
    --- FAIL: TestConformance/multiple_linter (0.04s)
        conformance_test.go:465: Failed getting artifact contents projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-linter: rpc error: code = NotFound desc = "projects/conformance-test/locations/global/apis/petstore/versions/1.0.0/specs/openapi/artifacts/conformance-openapitest-multiple-linter" not found in database

I couldn't identify why these were failing as the conformance tests aren't really unit tests - they start processes and move data around in ways that are hidden from the test suite. In addition, nothing was logged that indicated what the root cause might be.

[theganyo]

Original issue: #946

[theganyo]

Investigation reveals that at least part of the issue appears to be that the conformance relies on Id, but Id and Kind are not being stored in the YAML.