[MOOSE-354] FE: Group block left/right padding in editor

[GeoffDusome]

What does this do/fix?

Ports the group block padding fix from nexcess PR #25 back to Moose. This resolves two bugs:

1. When using the transparent background color setting on group blocks there should be no internal padding, even if a color theme is used.
2. The editor padding would appear different than the frontend depending on the color theme selected.

Approach: Instead of setting padding in each variation's JSON file, padding is now applied via CSS (in style.pcss and a new editor.pcss). This allows has-transparent-background to override it cleanly without needing !important escalation.

Changes:

• Removed spacing.padding from all group variation JSON files (10-white, 20-light, 30-dark, 40-brand)
• Updated style.pcss to apply themed padding via :is(:--light-themes, :--dark-themes) selector and add padding: 0 !important to transparent background case
• Added editor.pcss to mirror the frontend padding behavior in the block editor
• Updated editor.js to import the new editor.pcss

QA

Links to relevant issues

• MOOSE-354

Screenshots/video:

• Nested Group blocks no longer override default left/right editor padding: https://p.tri.be/i/e1MAU4

Pull request checklist

• I've added a changelog entry for these changes.
• I've linked to a relevant Jira issue.
• I've captured a screenshot or screencast of the changes and linked it above.

[GeoffDusome]

@dpellenwood @Vinsanity Do either of you know if, because this was an issue on learn.tri.be if I have to also make this update there, or do we port stuff back there?

[spadilha]

🍏 Just double check if the changes in package-lock.json was intentional.

[GeoffDusome]

🍏 Just double check if the changes in package-lock.json was intentional.

Every time I run lando start, npm install runs and then does that to the package.lock file. I don't know why.

[jamiepaul]

🟢

[dpellenwood]

@Vinsanity & @LayaTaal , Is this related to the discussion we had yesterday about padding on group blocks? If so, can we loop Geoff and Marina in on this convo before this gets merged?

[LayaTaal]

@Vinsanity & @LayaTaal , Is this related to the discussion we had yesterday about padding on group blocks? If so, can we loop Geoff and Marina in on this convo before this gets merged?

This is related @dpellenwood. I think we should go over this all once more with design to align on a permanent solution that works for them.