Add tests for Project euler problem 14 solution (TheAlgorithms#1713)

* 📦 NEW: Added solution for ProjectEuler-007

* 🐛 FIX: Spelling mistake fixes

* 👌 IMPROVE: changed variable name from `inc` to `candidateValue` and thrown error in case of invalid input

* 👌 IMPROVE: Modified the code

* 👌 IMPROVE: Added test case for ProjectEuler Problem001

* 👌 IMPROVE: Added test cases for Project Euler Problem 4

* 👌 IMPROVE: auto prettier fixes

* 📦 NEW: Testcases for Project Euler Problem 14

* Updated Documentation in README.md

* 👌 IMPROVE: code improvements

---------

Co-authored-by: Omkarnath Parida <omkarnath.parida@yocket.in>
Co-authored-by: pomkarnath98 <pomkarnath98@users.noreply.github.com>

Author: pomkarnath98

Project-Euler/test/Problem014.test.js

@@ -0,0 +1,15 @@
+import { expect } from 'vitest'
+import { findLongestCollatzSequence } from '../Problem014.js'
+
+describe('Longest Collatz Sequence', () => {
+  test.each([
+    [2, 1],
+    [13, 9],
+    [1000000, 837799]
+  ])(
+    'if limit is %i, then the Longest Collatz Sequence will be %i',
+    (a, expected) => {
+      expect(findLongestCollatzSequence(a)).toBe(expected)
+    }
+  )
+})