Replace calls to Form::hidden

[marcusmoore]

This PR replaces calls to Form::hidden with either plain html or, in one case, the @csrf directive.

Pages Affected

• https://snipe-it.test/admin/backups
• https://snipe-it.test/admin/labels

[what-the-diff]

PR Summary

• Switched to Standard HTML for Form Fields
  The form fields in our settings module were previously using a method Form::hidden which was a bit complex. The pull request has replaced these with the standard HTML <input type="hidden"> fields, providing simpler and more widely used code.

• Improvement in Security for Backup Generation Button
  Previously, the way our backup generation button in settings handled the CSRF (Cross-Site Request Forgery) token input was by using Form::hidden. Now, the PR updates this to use the @csrf directive, simplifying the code and enhancing the reliability of this input handling.