Enable the switch in TrustedCredentialsSettings

And match the behaviour of the dialog button that does the same thing,
so it only asks for confirmation when something is being irrevocably
deleted.

The dialog button should not be removed as it's used by system services
that deeplink to a specific cert to give the option of reviewing,
removing, or trusting it.

Bug: 31159682
Change-Id: I4fb3f38f8ab0e80e5c2dca0fc3d6d3bd4db26bb6