discount using metafield and rest from actual cart

Author: jonathanhamel4

discounts/rust/discounts/default/src/fetch.graphql.liquid

@@ -1,7 +1,7 @@
 query Input {
-  discountNode {
-    metafield(namespace: "$app:{{handle | replace: " ", "-" | downcase}}", key: "function-configuration") {
-      value
-    }
+  cart {
+      buyerIdentity {
+        email
+      }
   }
 }

discounts/rust/discounts/default/src/run.graphql.liquid

@@ -1,5 +1,24 @@
 query Input {
   fetchResult {
     body
+    status
+  }
+  cart {
+    deliveryGroups {
+      id
+    }
+    lines {
+      id
+      cost {
+        subtotalAmount {
+          amount
+        }
+      }
+    }
+  }
+  discountNode {
+    metafield(namespace: "$app:{{handle | replace: " ", "-" | downcase}}", key: "function-configuration") {
+      value
+    }
   }
 }