Description

As of 10.4-RC1, Reusable blocks can't be inserted in the Site Editor.

This issue is related to #30668, which presents the opposite logic for template parts. Original discussion in #30308

Step-by-step reproduction instructions

1. Go to the post editor.
2. Select any block and click on "Add to reusable blocks"
3. Go to the Site Editor.
4. Open the inserter and look for the recently created reusable block.

Expected behaviour

The recently created reusable block should be available in the site editor.

Actual behaviour

The recently created reusable block is not available in the site editor.

WordPress information

• WordPress version: 5.7
• Gutenberg version: 10.4-RC1
• Are all plugins except Gutenberg deactivated? Yes
• Theme used? TT1 Blocks