The oauth2_client class (and all its derived implementation) takes a `moodle_url $returnurl` in its constructor parameter. The $this->returnurl is only used in the context of login, through the `get_login_url()` method.

When implementing a logout OAuth client, you need to pass that redirecturl, which is not used. I argue this is a code smell, that can be fixed this way:

• Remove the $redirecturl parameter from all the constructors for oauth clients
• Remove the $redirecturl field from the class
• Pass a $redirecturl argument into the get_login_url function, where it's really used
• Edit the get_user_oauth_client function to remove the $currenturl parameter
• remove the $overrideurl in the get_user_oauth_client method in /repository/{googledocs,nextcloud,onedrive}/lib.php
• Find a way to pass the returnurl to the get_login_url(). This should be doable everywhere I've seen

Patch incoming