docs: Full fix for YouTube 153 Error

[ajitzero]

Regarding: https://github.com/simonw/til/blob/main/youtube/fixing-153-embed.md

On this page, I still see the "Error 153" message. With Dev Tools, I added the referral policy attribute below, and now it works for me.

We need to mention referrerpolicy="strict-origin-when-cross-origin" on the iframe to fix this issue.

Reference: https://developers.google.com/youtube/terms/required-minimum-functionality#embedded-player-api-client-identity