Fix error message reported due to authentication failure when fetching service metadata

[gathogojr]

Describe the bug

Fix error message reported due to authentication failure when fetching service metadata.

Version of the Project affected

ODataConnectedService v1.0.2

To Reproduce

Steps to reproduce the behavior:

1. Try to create a Connected Service using OData Connected Service Visual Studio extension against an OData service that requires authentication.
2. Review the error message returned. It has references to behaviour that was expected with legacy OData CodeGen tool.

Expected behavior

An error message relevant to the current OData Connected Service behaviour.

Actual behavior

A misleading, non-factual and incorrect error message.

Screenshots