buildWithBaseURLPath return only last part of url

[agrisvv]

Example of url
basepath: https://example.com/custom
assertion url: https://example.com/custom/login/idpname

Then function buildWithBaseURLPath returns:
https://example.com/custom/idpname

In result thow exception:
The response was received at https://example.com/custom/idpname instead of https://example.com/custom/login/idpname

Resolutions:
need to use all parts of url not only the last.

[joelpittet]

@agrisvv I am running into this exact issue too, thanks for posting it.

I'll post a PR for a potential fix.