Make sure correct dark mode colours get used in exports (#2492)

Also tweaks the colours of menus in dark mode to have a little higher
contrast. Fixed #2493

### Change Type

- [x] `patch` — Bug fix


[^1]: publishes a `patch` release, for devDependencies use `internal`
[^2]: will not publish a new version

---------

Co-authored-by: huppy-bot[bot] <128400622+huppy-bot[bot]@users.noreply.github.com>

packages/tlschema/src/styles/TLColorStyle.ts

@@ -160,9 +160,9 @@ export const DefaultColorThemePalette: {
 	},
 	darkMode: {
 		id: 'dark',
-		text: '#f8f9fa',
-		background: '#212529',
-		solid: '#28292e',
+		text: 'hsl(210, 17%, 98%)',
+		background: 'hsl(240, 5%, 8%)',
+		solid: '#010403',
 
 		black: {
 			solid: '#e1e1e1',