v2.3.2: Simplifies authentication process.

Refactors authentication logic to streamline the user verification process.
The changes include making the password parameter optional in the
`verifyCredentials` and `authenticate` methods, allowing for authentication
scenarios where a password may not be required. It also modifies how
identities are retrieved during session validation by directly fetching the
identity object from the entity manager using the object class stored in the
storage entity. This approach improves efficiency and reduces code
duplication. Additionally, stores the object class to the storage entity.