#4735 [BUG] Pyflyte Device Authentication flow does not support PKCE Issue created by EternalDeiwos ### Describe the bug Device Auth fails with a non-descript error message when attempting to authenticate against an IdP that enforces PKCE. ### Expected behavior Pyflyte should use PKCE if it is available with the IdP. At the very least, the error message should indicate the actual problem. ### Additional context to reproduce The IdP must be configured to enforce PKCE on the relevant client. Keycloak will respond with

400 Bad Request

if it is expecting a challenge and does not receive one. ### Screenshots No response ### Are you sure this issue hasn't been raised already? • Yes ### Have you read the Code of Conduct? • Yes flyteorg/flyte