Sensei overrides block theme's default styles

[donnapep]

Steps to Reproduce

1. Disable Sensei.
2. Download the Annalee theme from pNEWy-hkA-p2 and activate it.
3. In the site editor, edit the "Front Page" template.
4. Scroll down to the "Ready to transform your life?" section.
5. In a separate tab, enable Sensei.
6. Copy the URL from the other tab and paste in the new tab.
7. Scroll down to the "Ready to transform your life?" section.
8. Note the (subtle) differences in the font styles.

What I Expected

The styles to be inherited from the theme.

What Happened Instead

Sensei is adding its own styles that are overriding the theme's.

Context / Source

This issue was introduced in https://github.com/Automattic/sensei/pull/6066. The proper fix would be to only load Learning Mode CSS for the Learning Mode templates, but not sure if that's possible.

Ref: p6rkRX-6Ia-p2

Before

After

[donnapep]

May be solved by fix for #7227.

[iamtakashi]

Thanks for sorting this out, @donnapep!