Added the error coverage for giftCardAccount query (#8456)

* Added the error coverage for giftCardAccount query

* Update giftcard-account.md

Co-authored-by: Kevin Harper <[email protected]>

Author: dineshvb

src/guides/v2.3/graphql/queries/giftcard-account.md

@@ -69,3 +69,10 @@ Attribute |  Data Type | Description
 `balance` | Money | Returns the currency and remaining balance of the gift card
 `code` | String | Returns the gift card code
 `expiration_date` | String | Returns the date when the gift card expires, if any
+
+## Errors
+
+Error | Description
+--- | ---
+`Gift card not found` | The specified `gift_card_code` value does not exist in the `giftcardaccount` table, or the full amount has already been redeemed.
+`Field GiftCardAccountInput.gift_card_code of required type String! was not provided` | The value specified in the `GiftCardAccountInput.gift_card_code` argument is empty.