fix(auth): SAML authnContext parameter should be an array (#5290)

* saml auth: `authnContext` must be a list now

This fixes

    this.options.authnContext.forEach is not a function

when trying to login via SAML on wiki-js 2.5.281.

Reason for that is that `authnContext` must be a list now which is
apparently a breaking change that was missed while upgrading
passport-saml[1].

Resolves #5289

[1] https://github.com/node-saml/passport-saml/pull/615

* fix(auth): split authnContext for SAML authenticaiton module

Co-authored-by: Nicolas Giard <github@ngpixel.com>

server/modules/authentication/saml/authentication.js

@@ -21,7 +21,7 @@ module.exports = {
       wantAssertionsSigned: conf.wantAssertionsSigned,
       acceptedClockSkewMs: _.toSafeInteger(conf.acceptedClockSkewMs),
       disableRequestedAuthnContext: conf.disableRequestedAuthnContext,
-      authnContext: conf.authnContext,
+      authnContext: _.split(conf.authnContext, '|'),
       racComparison: conf.racComparison,
       forceAuthn: conf.forceAuthn,
       passive: conf.passive,