fix(stories): move color metadata to frontmatter (#95282)

Small change to adjust the color story metadata.

Author: natemoo-re

static/app/styles/colors.mdx

@@ -1,3 +1,8 @@
+---
+title: Colors
+description: Sentry has a flexible, tiered color system that adapts to both light and dark mode. Our color palette consists of neutral grays and 6 accent colors.
+---
+
 import {useTheme} from '@emotion/react';
 import styled from '@emotion/styled';
 
@@ -184,10 +189,6 @@ return (
 </SideBySide>
 ); }
 
-# Colors
-
-Sentry has a flexible, tiered color system that adapts to both light and dark mode. Our color palette consists of neutral grays and 6 accent colors.
-
 ## Grays
 
 There are 5 shades of gray, ranging from Gray 500 (darkest) to Gray 100 (lightest).