fix: unmarshal CallView result as []byte before asserting uint64

CallView returns JSON-encoded []byte, not the raw Go type.
The Check*Balance functions were doing res.(uint64) which panics
because res is actually []byte. Use JSONUnmarshalUint64 helper
(analogous to existing JSONUnmarshalFloat64) to properly decode
the result.

Signed-off-by: Soumya Mohapatra <mohapatras@microsoft.com>

Author: Soumya Mohapatra

integration/token/fungible/support.go

@@ -416,7 +416,7 @@ func CheckIssuedBalance(network *integration.Infrastructure, issuer *token3.Node
 		TokenType: typ,
 	}))
 	gomega.Expect(err).NotTo(gomega.HaveOccurred())
-	balance := res.(uint64)
+	balance := JSONUnmarshalUint64(res)
 	gomega.Expect(balance).To(gomega.Equal(expected), "issued balance: got %d, expected %d", balance, expected)
 }
 
@@ -426,7 +426,7 @@ func CheckRedeemedBalance(network *integration.Infrastructure, issuer *token3.No
 		TokenType: typ,
 	}))
 	gomega.Expect(err).NotTo(gomega.HaveOccurred())
-	balance := res.(uint64)
+	balance := JSONUnmarshalUint64(res)
 	gomega.Expect(balance).To(gomega.Equal(expected), "redeemed balance: got %d, expected %d", balance, expected)
 }
 
@@ -436,7 +436,7 @@ func CheckOutstandingBalance(network *integration.Infrastructure, issuer *token3
 		TokenType: typ,
 	}))
 	gomega.Expect(err).NotTo(gomega.HaveOccurred())
-	balance := res.(uint64)
+	balance := JSONUnmarshalUint64(res)
 	gomega.Expect(balance).To(gomega.Equal(expected), "outstanding balance: got %d, expected %d", balance, expected)
 }
 
@@ -1254,6 +1254,22 @@ func JSONUnmarshalFloat64(v interface{}) float64 {
 	return s
 }
 
+func JSONUnmarshalUint64(v interface{}) uint64 {
+	var s uint64
+	switch v := v.(type) {
+	case []byte:
+		err := json.Unmarshal(v, &s)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+	case string:
+		err := json.Unmarshal([]byte(v), &s)
+		gomega.Expect(err).NotTo(gomega.HaveOccurred())
+	default:
+		panic(fmt.Sprintf("type not recognized [%T]", v))
+	}
+
+	return s
+}
+
 type deleteVaultPlatform interface {
 	DeleteVault(id string)
 }