Apply Coding Standards

[n7studios]

Summary

Applies PSR-12 coding standards to the API class, with some exclusions to prevent conflicts with Squiz coding standards.

Runs coding standard checks for PRs on the GitHub Action

Testing

Existing tests pass.

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• Code meets WordPress Coding Standards for PHP, HTML, CSS and JS
• Security and Sanitization requirements have been followed
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)