Throw Exception When Only 'Bearer' is Specified in Authorization Header

[marevol]

We have updated the AccessTokenHelper class to enhance security measures. Previously, our code did not throw an exception when only "Bearer" was specified in the Authorization header without an accompanying token. This update rectifies this oversight. Now, when the Authorization header contains only "Bearer" with no token, our system will throw an InvalidAccessTokenException. This change ensures that invalid or incomplete authorization attempts are properly handled, improving the robustness of our authorization process.