core-api: unique storage of saml sessions as well

.changeset/sour-badgers-cry.md

@@ -2,4 +2,4 @@
 '@backstage/core-api': patch
 ---
 
-GitHub Auth Api uses provider.id to build storage key name.
+Use auth provider ID to create unique session storage keys for GitHub and SAML Auth.

packages/core-api/src/apis/implementations/auth/saml/SamlAuth.ts

@@ -63,7 +63,7 @@ class SamlAuth implements ProfileInfoApi, BackstageIdentityApi, SessionApi {
 
     const authSessionStore = new AuthSessionStore<SamlSession>({
       manager: sessionManager,
-      storageKey: 'samlSession',
+      storageKey: `${provider.id}Session`,
     });
 
     return new SamlAuth(authSessionStore);