[Auth] Add SAML provider to the compat layer (#5689)

* Add SAML provider to the compat layer

* Add changeset

Author: sam-gc

.changeset/big-rocks-scream.md

@@ -0,0 +1,6 @@
+---
+"@firebase/auth-compat": patch
+"@firebase/auth": patch
+---
+
+Add SAMLAuthProvider to the compatability layer (it was missing before)

packages/auth-compat/index.ts

@@ -101,7 +101,7 @@ function registerAuthCompat(instance: _FirebaseNamespace): void {
         GithubAuthProvider: impl.GithubAuthProvider,
         GoogleAuthProvider: impl.GoogleAuthProvider,
         OAuthProvider: impl.OAuthProvider,
-        //   SAMLAuthProvider,
+        SAMLAuthProvider: impl.SAMLAuthProvider,
         PhoneAuthProvider: CompatAuthProvider,
         PhoneMultiFactorGenerator: impl.PhoneMultiFactorGenerator,
         RecaptchaVerifier: CompatRecaptchaVerifier,