fix #61
The issue was that programs.firefox.enable create a /etc/firefox/policies/policies.json file that take precedence over the one packaged alongside firefox.
So we have to use programs.firefox.policiesto set Phoenix policies in this case.
fix #61
The issue was that `programs.firefox.enable` create a `/etc/firefox/policies/policies.json` file that take precedence over the one packaged alongside firefox.
So we have to use `programs.firefox.policies`to set Phoenix policies in this case.