Shibboleth special groups are not working

[Leano1998]

Describe the bug
When you're using shibboleth as authentication method and want to use the special-group functionality, these special groups are not set. I think this might be the same reason why the bug reported in #9226 exits. As reported there, the problem lies in the newly introduced if condition in #9130. I digged a bit deeper into this and found, that if I overwrite the areSpecialGroupsApplicable() method in the ShibAuthentication.java according to the overwrite made in IPAuthentication.java always returning true, it works. I'm still analysing, what is the real cause behind this (so why areSpecialGroupsApplicable() does not return true for shibboleth if needed), but I wanted to post this already.

To Reproduce
Steps to reproduce the behavior:

1. Activate shibboleth authentication on your backend
2. Set a group mapping for special-groups as described in the docs.
3. Login with a user-account via shibboleth, which has the needed affiliation
4. Check if the special-groups appear in your profile

Expected behavior
The user should be placed in the corresponding special-groups.

Related work

• Shibboleth special groups don't populate when IP authentication also used in 7.6.1 #9226
• Authentication Method related special groups are put in claim set even if a different authentication method is used #9130

[Leano1998]

It seems as context.getAuthenticationMethod() returns null for the ShibAuthentication in AuthenticationMethod.java:

    public default boolean areSpecialGroupsApplicable(Context context, HttpServletRequest request) {
        return getName().equals(context.getAuthenticationMethod());
    }