Fix: Ensure autogenerate_code_verifier defaults to True in from_client_config

google_auth_oauthlib/flow.py

@@ -161,6 +161,8 @@ def from_client_config(cls, client_config, scopes, **kwargs):
         # these args cannot be passed to requests_oauthlib.OAuth2Session
         code_verifier = kwargs.pop("code_verifier", None)
         autogenerate_code_verifier = kwargs.pop("autogenerate_code_verifier", None)
+        if not code_verifier and autogenerate_code_verifier is None:
+            autogenerate_code_verifier = True
 
         (
             session,