Update Get-OspreyUserHiddenRule

[syne0]

A few problems with this, the main one being that I have not found a single case where a hidden inbox rule was actually used during a BEC. The script is problematic, in that it needs to use impersonation, doesn't work on an account with MFA, and uses EWS.

I really don't think this is sticking around, but if there's a better way to get this now that graph exists, it's worth looking at this.

I'll need to add a hidden inbox rule on one of my dev accounts to test this.

[syne0]

flag in get-inboxrule to show hidden seems to work fine, added it to the normal user inbox rule function