Update tokens to v6.1 (#153722)

This PR is to update the token version to v6.1. 
* This version fixes https://github.com/flutter/flutter/issues/153271
* Change the chip default border color from `ColorScheme.outline` to `ColorScheme.outlineVariant`. The Chips' border color is softened to improve visual hierarchy between chips and buttons

examples/api/test/material/material_state/material_state_border_side.0_test.dart

@@ -50,7 +50,7 @@ void main() {
       await tester.tap(find.byType(FilterChip));
       await tester.pumpAndSettle();
 
-      expect(findBorderColor(const Color(0xff79747e)), findsOne);
+      expect(findBorderColor(const Color(0xffcac4d0)), findsOne);
     },
   );
 }