Grant readwrite to root snippets for all users (#21940)

* Grant Snippets root collection for all users

* update perms path

* update cypress test

* Update repro for #17268

* remove trailing spaces

* don't run migration on existing EE instances

* fix migration failed in mysql and mariadb

* run migration for new instances only

Co-authored-by: Nemanja <31325167+nemanjaglumac@users.noreply.github.com>