Strip out utm_internal

[fmarier]

Sample URLs:

• https://platform.billtobox.be/login2/users/registration?utm_internal=commercialsite&_ga=2.203742230.707792121.1633425719-1654755149.1633425719
• https://www.plex.tv/blog/plex-pro-week-24-does-your-server-suck-energy/?utm_internal=pro_week_tim_blog_24

Not a very common one, but it's also in https://github.com/jparise/chrome-utm-stripper/issues/65