Sanitize nonce check.

[mauteri]

Description of the Change

Sanitize nonce check.

Closes #611

How to test the Change

Changelog Entry

Security - Vulnerability

Credits

Props @mauteri

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[what-the-diff]

PR Summary

• Enhanced Data Validation in User Profile Fields
  Changes were made in file class-user.php to further improve the system's immune to untrusted data and unwanted behaviours. The save_profile_fields method now uses additional functions sanitize_text_field and wp_unslash to handle and clean up the profile field data - by removing unnecessary slashes and sanitizing text field input. This change is significant in enhancing the overall security of the system.

• Improved Post Content Handling in Posts
  Modifications were done in the file class-post.php to improve how the system handles null post content. The get_content method now includes a null-coalescing operator to return an empty string in scenarios where post_content may be null. This can prevent unexpected errors that would otherwise occur if the system attempts to interact with null content.