Columns block: blockGap enabled in theme.json but no "Block spacing" control in "Dimensions" panel

[alexandrebuffet]

Description

The blockGap option for the Columns block appeared to have been introduced with #34630, but the "Block spacing" control no longer appears in the Dimensions panel.

Tested up with WordPress 5.9-RC2 and Twenty Twenty-Two, only padding and margin controls shows up.

On WordPress 5.8.3 + Gutenberg 12.3.2 and a custom block theme, even with "blockGap": true in theme.json only padding and margin controls shows up.

Step-by-step reproduction instructions

1. Add the Columns core block in a page or template
2. "Block spacing" control no longer appears in the Dimensions panel

Screenshots, screen recording, code snippet

Environment info

• WordPress 5.9-RC2 with Twenty Twenty-Two
• WordPress 5.8.3, Gutenberg 12.3.2 with Custom Block Theme

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

[annezazu]

This is due to this change: #37360 (comment) A fix will come in 12.4: #37436