Use a numbered pre-named set of user colors instead of random. Closes #1974

web/stories/Colors.stories.mdx

@@ -22,6 +22,21 @@ Toggle dark mode on and off in the above toolbar to see how these colors look on
 
 <ColorRow colors={['theme-background', 'theme-background-secondary', 'popover-background']} />
 
+## User Colors
+
+<ColorRow
+  colors={[
+    'theme-user-colors-1',
+    'theme-user-colors-2',
+    'theme-user-colors-3',
+    'theme-user-colors-4',
+    'theme-user-colors-5',
+    'theme-user-colors-6',
+    'theme-user-colors-7',
+    'theme-user-colors-8',
+  ]}
+/>
+
 ## Status
 
 <ColorRow