fix: simplify logic core-charge

Signed-off-by: Chloe <pinkcloudvnn@gmail.com>

lib/shopify/queries/product.ts

@@ -35,21 +35,3 @@ export const getProductRecommendationsQuery = /* GraphQL */ `
   }
   ${productFragment}
 `;
-
-export const getProductVariantQuery = /* GraphQL */ `
-  query getProductVariant($id: ID!) {
-    node(id: $id) {
-      ... on ProductVariant {
-        id
-        title
-        selectedOptions {
-          name
-          value
-        }
-        coreVariantId: metafield(namespace: "custom", key: "coreVariant") {
-          value
-        }
-      }
-    }
-  }
-`;