fix: change publish button colors in create a gallery page

[patricio0312rev]

[Galleries] Change "Publish" button to primary colours

Summary

• Publish button colors have been changed to the ones mentioned in the ticket. Dark mode is also supported for this button.

Steps to reproduce

1. Run the app in local or testing_e2e mode.
2. Make sure you have a wallet connected.
3. Go to Create a gallery page.
4. Look at the bottom of the page and see the magic ✨

Checklist

• I checked my UI changes against the design and there are no notable differences
• I checked my UI changes for any responsiveness issues
• I checked my (code) changes for obvious issues, debug statements and commented code
• I opened a corresponding card on Clickup for any remaining TODOs in my code
• I added a short description on how to test this PR (if necessary)
• I added a storybook entry for the component that was added (if necessary)
• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged