Don't allow additional sources if 'Any' base policy selected

Problem/Motivation

A CSP policy may have additional non-network sources (e.g. data:), but these don't appear to be applicable to Permissions-Policy, so the corresponding policy optimization can be simplified.

Steps to reproduce

Proposed resolution

Update PermissionsPolicy::reduceSourceList() to only output directive=* if the directive contains a wildcard source.

Remaining tasks

API changes

Permissions Policy directives will no longer output non-network sources along with an "any" wildcard source.