Description

Apologies for this strange title but I'm struggling to find the best way to explain this. Essentially, one is able to load the site editor within the site editor due to the fact that if you click on a link to a post within a query block while in the site editor, it loads the post as if you were viewing it on the front end. cc @priethor as this seems pretty serious to fix.

Step-by-step reproduction instructions

1. Have a site using FSE and TT1 Blocks.
2. Open the site editor.
3. Scroll down to a post within the query block that you've created.
4. Click on the post title link/open the link and see the post load within the editor rather than taking you elsewhere.
5. Notice that you can then click "edit site" while still in the site editor.

Expected behaviour

I expect to not be able to click a link to a post and have it load within the site editor itself.

Actual behaviour

I am able to click on a link in the post within the site editor and have that individual post load an entire experience within the site editor itself.

Screenshots or screen recording (optional)

Screenshot:

Video:

WordPress information

• WordPress version: 5.7
• Gutenberg version: 10.3.2
• Are all plugins except Gutenberg deactivated? Yes
• Are you using a default theme (e.g. Twenty Twenty-One)? TT1 Blocks

Device information

• Device: Desktop
• Operating system: MacOS
• Browser: Chrome v 89