chore(picker): update metadata.json

Author: marissahuysentruyt

components/picker/dist/metadata.json

@@ -278,6 +278,7 @@
     "--spectrum-gray-100",
     "--spectrum-gray-200",
     "--spectrum-gray-300",
+    "--spectrum-gray-50",
     "--spectrum-gray-500",
     "--spectrum-gray-600",
     "--spectrum-gray-700",