Fix type conversion for last 4 digits extraction

Corrected the type conversion from 'string' to 'String' for proper functionality.

Author: anitahy73

Sprint-2/2-mandatory-errors/3.js

@@ -1,5 +1,5 @@
 const cardNumber = 4533787178994213;
-const last4Digits = string(cardNumber).slice(-4);
+const last4Digits = String(cardNumber).slice(-4);
 console.log(last4Digits);
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working