Only load gallery styling rules when galleries are on the page
- Double load styling rules in legacy modules so we have time for
cached pages to catch up
- Double loading styles is acceptable for 30 days. There is no better way.
- Load gallery css when gallery tag invoked.
- Visit a page with a gallery tag and purge it, note styles are present.
- Visit a page without a gallery tag and purge it, note styles are not present