Description

Hi, I noticed a problem with custom color palette in the site editor (as the title).

Step-by-step reproduction instructions

1. Go to Appearance > Editor
2. Open Styles > Colors > Palette > Custom (Add color) > Click "Done" & Save
3. Back to Browse style
4. Change to another style and Save
5. Check if the custom color has been saved in the previous style.

Screenshots, screen recording, code snippet

Environment info

• WordPress 6.1.1
• Gutenberg 15.2.0
• Theme Twenty Twenty-Three

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