Added tests for component checkout api endpoint

[marcusmoore]

Description

This PR adds tests for the api endpoint for component checkouts.

Type of change

• Testing

[what-the-diff]

PR Summary

• Introduction of a New Test File for Component Checkout
  A new test file named ComponentCheckoutTest.php has been included to ensure the component checkout feature runs effectively. It covers aspects such as authority checks for checkout actions, handling of components that don't exist, requirement checking for necessary fields during checkout, restricting checkout quantities based on stock availability, recording checkout activities in the database and support for requests that involve multiple companies in a checkout.

• Improvements to CustomTestMacros.php
  The file CustomTestMacros.php has been upgraded with a new function assertPayloadContains. This new function verifies the existence of certain keys within the response data, which confirms that the response contains the expected information.