Missing test scenario for error 429 #217

Problem description
Per Commonalities all errors of the API must be covered by a test scenario.
There is no test scenario for the 429 error response.

Expected action
Add the test scenario(s) for the error 429

Additional context
FYI Commonalities r4.4 provides both the base error response catalogs and corresponding test cases here: https://github.com/camaraproject/Commonalities/blob/r4.4/artifacts/testing/sample-service-template.feature