Sort npm audit pending list by severity

[Fryguy]

@jrafanie Please review. This was used to rebuild the yarn audit lists in ManageIQ/manageiq-ui-classic#9329 and ManageIQ/manageiq-ui-service#1947

cc @GilbertCherrie

[jrafanie]

Weird, it failed.

  1) BlacklistedEvent.seed re-seeds deleted event filters
     Failure/Error: expect(described_class.count).to eq(total_blacklist_entry_count - 1)

       expected: 129
            got: 127

       (compared using ==)
     # ./spec/models/blacklisted_event_spec.rb:14:in `block (3 levels) in <top (required)>'

Sporadic failure?

[Fryguy]

@jrafanie More likely fallout from the work being done in #19707