Error saving SSO setings. "Response content-type is not XML"

Overview: FOLIO throws an error if you save an Identity Provider URL that returns a content type header of application/samlmetadata+xml

Steps to Reproduce:

1. Login to a FOLIO instance.
2. Go to Settings>organization>SSO settings
3. put in a URL that returns a header with content-type application/samlmetadata+xml (ask ttolstoy for that URL)
4. Add some data in the other fields in order to prevent form warnings
5. If Identity Provider URL field is red, remove one character from the url and then type it back. Now you should be able to hit save.
6. Click save
   Expected Results: The SSO configuration is successfully saved.

Actual Results: Error is returned, saying "Response content-type is not XML"

Additional Information:
Hitting the URL, you can see that the content-type returned is application/samlmetadata+xml Allowing that one together would most likely solve the issue.

Seems to me that row 40 in https://github.com/folio-org/mod-login-saml/blob/master/src/main/java/org/folio/util/UrlUtil.javaUrlUtil.java should be a bit more allowing