Update MinimalWebAuthenticationTestCase so that it doesn't use an authentication factory as specified in the test description

MinimalWebAuthenticationTestCase defines a ServerSetup class that ensures that an application security domain mapping to a security domain is used instead of an authentication factory. However, this class is currently not being used although the test description mentions that it should be used.

See https://github.com/wildfly/wildfly/blob/master/testsuite/integration/elytron/src/test/java/org/wildfly/test/integration/elytron/web/MinimalWebAuthenticationTestCase.java#L38