[4.x] Fix utility permissions not showing when using route caching

[duncanmcclean]

This pull request attempts to fix an issue where the permissions for utilities are missing when you're using route caching.

From what I can tell, without route caching it looks like the utilities are booted before the permissions are booted but with route caching, the permissions are booted before utilities are.

To workaround this, we've made the boot method in the UtilitiesRepository fluent so we can do Utility::boot()->all() to ensure utilities have always been booted before we use them.

Fixes #8691.

[jasonvarga]

• Put guard clause inside boot so it does nothing if already booted.
• In all, always boot().
• In find and findBySlug, use $this->all() instead of $this->utilities
• In routes you might be able to remove boot() since it calls all(), but test it out.