TypeError in getRootMicrosoftGraphUri

[Loki3000]

Hi there!

        $openIdConfiguration = $this->getOpenIdConfiguration($tenant, $version);
        return 'https://' . $openIdConfiguration['msgraph_host'];

After an unsuccessful attempt to get the configuration, getOpenIdConfiguration returns an empty string. As a result, the next line triggers a TypeError. It's not an exception, so it isn't caught by other error handlers.