Fix mlflow api calls remove double //
Summary
The current calls to the mlflow tracking server have a double backslash in them, and this breaks the calls and returns a Internal server error
Steps to reproduce
When you create a experiment repository, Internal server error is returned
What is the current bug behavior?
a double backslash is present in the API call
What is the expected correct behavior?
the api call returns what expected
Relevant logs and/or screenshots
LOGS
<Put log output here>
Possible fixes
/cc @thomas_ambrosys /cc @fabian.emmerich