Newest `lakefs` breaks repository creation test

[nicholasjng]

TL,DR: The repository creation error code is now also 409 (yay!), which is a departure from the behavior of v1.0.0.

Reproducible by testing on current main against e.g. a treeverse/lakefs:latest Docker container.

Error:

>           raise ApiException(http_resp=r)
E           lakefs_sdk.exceptions.ApiException: (409)
E           Reason: Conflict
E           HTTP response headers: HTTPHeaderDict({'Content-Type': 'application/json', 'X-Content-Type-Options': 'nosniff', 'X-Request-Id': '48f1ed1d-4c51-440c-bb43-85edb9f2c401', 'Date': 'Mon, 27 Nov 2023 20:21:48 GMT', 'Content-Length': '52'})
E           HTTP response body: {"message":"error creating repository: not unique"}

The fix is as easy as changing the expected response code to 409 as well as the error text.