fix(curriculum): correct validation example in encapsulation lesson (freeCodeCamp#64906)

Co-authored-by: Jeevankumar <[email protected]>

Author: Jeevankumar-s

curriculum/challenges/english/blocks/lecture-understanding-object-oriented-programming-and-encapsulation/68420be9af9d89620af7944a.md

@@ -144,13 +144,15 @@ class Wallet:
        return self.__balance
 
 acct_one = Wallet()
-acct_one.deposit(4) # ValueError('Amount must be positive')
-print(acct_one.get_balance()) # 0
+acct_one.deposit(3)
+print(acct_one.get_balance()) # 3
 
 acct_one.deposit(50)
-print(acct_one.get_balance()) # 50
-acct_one.withdraw(-8) # ValueError('Amount must be positive')
-acct_one.withdraw(58) # ValueError('Insufficient funds')
+print(acct_one.get_balance()) # 53
+
+acct_one.deposit(-4)  # ValueError: Amount must be positive
+acct_one.withdraw(-8) # ValueError: Amount must be positive
+acct_one.withdraw(58) # ValueError: Insufficient funds
 ```
 
 As you can see, the `__validate` method is private, and runs behind the scenes in the `deposit()` and `withdraw()` public methods to make sure the amount is always valid.