Notes should be optional

[Timothy Vincent N. Pinawin]

Summary
Inputs for Notes should be optional, not required when creating a new expense record

Steps to Produce:

1. Go to Expense tab
2. Click on Add
3. Set the Category to Grocery
4. Set the Item Name to Flour
5. Set the Amount to ₱1500.00
6. Click Add

Expected Results:
It should have created the new expense record and generated in the expense database

Actual Results:
There was an input validation stating to input in the Notes field.

See 07-CSHAddExpense, Iteration 1-4 for more details

[Andres Paolo A. Dalisay]

fixed with 4943549

[Andres Paolo A. Dalisay]

fixed with 07ed533

wrong commit earlier