fix: re-apply register Passkey API v2 (#5990)

Revert "fix: REVERT register Passkey API v2"

internal/api/authz/user.go

@@ -0,0 +1,16 @@
+package authz
+
+import (
+	"context"
+
+	"github.com/zitadel/zitadel/internal/errors"
+)
+
+// UserIDInCTX checks if the userID
+// equals the authenticated user in the context.
+func UserIDInCTX(ctx context.Context, userID string) error {
+	if GetCtxData(ctx).UserID != userID {
+		return errors.ThrowUnauthenticated(nil, "AUTH-Bohd2", "Errors.User.UserIDWrong")
+	}
+	return nil
+}