OAuth 2.0 specifies that [the redirection endpoint URI MUST NOT include a fragment component](https://www.rfc-editor.org/rfc/rfc6749#section-3.1.2). Authlib should return a bad request http response (400) when any of the `redirect_uris` contains a [fragment identifier](https://en.wikipedia.org/wiki/URI_fragment) at client registration.