Update google/auth/crypt/rsa.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: daniel-sanche

google/auth/crypt/rsa.py

@@ -98,7 +98,7 @@ class RSASigner(base.Signer, base.FromServiceAccountMixin):
             public key or certificate.
 
     Raises:
-        ImportError: if called with an rsa.key.PublicKey, when the rsa library is not installed
+        ImportError: if called with an rsa.key.PrivateKey, when the rsa library is not installed
         ValueError: if an unrecognized public key is provided
     """