Left sidebar (admin-menu): match Calypso and wp-admin color schemes

[fushar]

There seems to be discrepancies in certain admin color schemes between Calypso and wp-admin screens for the left sidebar.

Examples below are using Classic Bright:

---

Site card (for Default admin interface style)

Calypso	wp-admin

Differences:

1. Site card borders: wp-admin's seems to have top and bottom borders.
2. Site card background also have different colors in some color schemes.
3. Coming soon badge background colors.
4. Margins around the "Free domain" upsell banner.

---

Sidebar menus (both Default and Classic?)

Calypso	wp-admin

---

Cleaning up "navredesign" variables

Can we now remove the --color-navredesign-sidebar-menu-* variables introduced from the following PRs?

• Nav Redesign: Fix inconsistent submenu colors #90193
• Color Schemes: update sidebar styles to better match wp-admin #92397

They are confusing. IMO, we should have the same set of color definitions for both Default and Classic styles, and they need to match wp-admin's definitions.

[davemart-in]

Do we need to address this across all color schemes?

[fushar]

Yes, we need to audit all color schemes. I see that some already match, and some don't.

[ryelle]

The icons on the Calypso menus are also not uniform, items with children are a different color than the other icons:

	wp-admin	Calypso
Aquatic
Classic Blue
Light

Sakura's submenu color is also different between the two. In this case, I think the Calypso menu looks better, so the fix would need to happen wherever those colors are set (here?).

wp-admin	Calypso