use null instead of undefined

web/src/stores/transactions.ts

@@ -17,12 +17,12 @@ export interface Transaction {
     TransferAccount: string;
     CategoryGroup: string;
     Category: string;
-    CategoryID: string | undefined;
+    CategoryID: string | null;
     Memo: string;
     Status: string;
     GroupID: string;
     Payee: string;
-    PayeeID: string | undefined;
+    PayeeID: string | null;
     Amount: number;
     Reconciled: boolean;
     Account: string;