revokeToken method
Revokes the current token at the authorization server and clears it locally.
Implementation
Future<void> revokeToken() async {
if (_currentToken != null) {
try {
await _client.revokeToken(token: _currentToken!.accessToken);
} catch (e) {
// Even if remote revocation fails, drop the local token.
}
}
clearToken();
}