Skip WP Handling of 404s for static files

[wpscholar]

Proposed changes

Allow skipping of WP 404 handling for static files. Update code to fix an issue where updating the cache level setting didn't always work properly.

Type of Change

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation Update (if none of the other choices apply)