Identity: Unfurl UserID and Email in pkg/api to user identity.Requester (#76112)

* Unfurl OrgRole in pkg/api to allow using identity.Requester interface

* Unfurl Email in pkg/api to allow using identity.Requester interface

* Update UserID in pkg/api to allow using identity.Requester interface

* fix authed test

* fix datasource tests

* guard login

* fix preferences anon testing

* fix anonymous index rendering

* do not error with user id 0

pkg/services/auth/identity/requester.go

@@ -87,3 +87,21 @@ func IntIdentifier(namespace, identifier string) (int64, error) {
 
 	return 0, ErrNotIntIdentifier
 }
+
+// UserIdentifier converts a string identifier to an int64.
+// Errors if the identifier is not initialized or if namespace is not recognized.
+// Returns 0 if the namespace is not user or service account
+func UserIdentifier(namespace, identifier string) (int64, error) {
+	userID, err := IntIdentifier(namespace, identifier)
+	if err != nil {
+		// FIXME: return this error once entity namespaces are handled by stores
+		return 0, nil
+	}
+
+	switch namespace {
+	case NamespaceUser, NamespaceServiceAccount:
+		return userID, nil
+	}
+
+	return 0, nil
+}