Enable on browser startup breaks 'Main frame only' option.

[mabequinho]

Describe your issue here.

Your environment

• Version 2.8.0
• FF 118.0, Fedora 39

Steps to reproduce

• Configure to block 'Main frame only'
• Check 'Enable on browser startup'
• Restart browser
• Open a link with embed video, used link

Screencast.from.2023-10-05.14-45-03.webm

Expected behaviour

Youtube website being blocked while allowing embed videos.

Actual behaviour

Extensions prevents to load youtube embed video after browser restart.