IDPEntry ID cannot be used to determine URL of ECP endpoint

[nawatts]

See sections 3.4.1.3.1 and 8.3.6 of https://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf

The syntax of such an identifier is a URI of not more than 1024 characters in length. It is
RECOMMENDED that a system entity use a URL containing its own domain name to identify itself.

[tptee]

👍