Missing "Back" button in Document bar in focused editor coming from page

[stokesman]

Description

When editing a page in the Site editor and entering focused mode to edit a template or template part there is supposed to be a "Back" button in the Document bar.

Step-by-step reproduction instructions

1. Edit a page in the Site editor
2. Either:
   • Select a template part and click "Edit" in its toolbar
   • Click "Edit template" from the "Template options" menu in the Document summary panel
3. Note that there is no "Back" button in the Document bar

Screenshots, screen recording, code snippet

The following demonstrates the issue for both templates and template parts and at the 19 second mark also demonstrates how the "Back" button does appear if you edit a template part when already editing the template.

missing-back-button-doc-bar.mp4

Environment info

• WP 6.7.1 with Gutenberg plugin at trunk
• Chrome
• macOS

Please confirm that you have searched existing issues in the repo.

• Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

• Yes

Please confirm which theme type you used for testing.

• Block
• Classic
• Hybrid (e.g. classic with theme.json)
• Not sure