Disable UrlbarProviderInterventions

@cypherpunks1 said that urlbar interventions are not disabled in Tor Browser, and that the preference we are using (browser.urlbar.update1.interventions) is obsolete (see #40783 (comment 2838323)).

I am not familiar with this part of Firefox. From a quick search, I found that they can be still disabled with enterprise policies.

We should check why we disabled them in the first place, if it's still needed, or if we can keep them enabled.