Make the parameter "realm" optional

[foliengriller]

Currently, each call needs a parameter "realm" as first argument. As we only have one realm we are working with (we do not use the master realm), this parameter does not make lot of sense for us. As the realm is already defined in the httpClient, it could be taken from there and overwritten if necessary.

So my proposal would be as follows:

public function get(string $userId, ?string $realm = null): UserRepresentation
    {
        $realm = $this->getRealm($realm);
       ....

and, in Resource.php

    public function getRealm(string|null $realm): string
    {
        if (!$realm) {
            return $this->realm;
        }

        return $realm;
    }

I can try to create a merge request, but as it will be a breaking change, I want to ask first. Maybe there is also a better approach to solve the problem.