SSL/TLS Add exception dialog not themed

[Nirojan Vythilingam]

Firefox version: 64 b12
OS: macOS 10.14.1

Dialog to add insecure connection exception doesn't appear to be themed.

Steps to reproduce

1. Visit https://expired.badssl.com/
2. Click on Advanced and then Add exception
3. You should see the dialog that isn't themed properly

[Pat Johnson]

Thanks for the report! Should be fixed in the latest version :)