fix(themes): use proper color from dark palette

Author: brandyscarney

core/src/themes/ios/dark.tokens.ts

@@ -17,7 +17,7 @@ export const darkTheme: DarkTheme = {
     350: '#595959',
     400: '#666666',
     450: '#737373',
-    500: '#898989',
+    500: '#808080',
     550: '#8c8c8c',
     600: '#999999',
     650: '#a6a6a6',