Add unit tests for generating a data source definition from Swagger

[rdimitrov]

The following issue is about adding unit tests for https://github.com/mindersec/minder/pull/5283.

This is needed so we can ensure we don't accidentally break the generation part.

[gajananan]

@rdimitrov , I can pick this one. (also thought of picking 4699)

[rdimitrov]

That would be great, @gajananan 💯 I'll assign you to the issue 👍