Move exchanging of XMPP contacts to account confirmation

Since the ejabberd service is now being enabled after the confirmation,
we also need to move the exchanging of roster contacts to that point.

spec/services/create_account_spec.rb

@@ -65,34 +65,6 @@ RSpec.describe CreateAccount, type: :model do
     end
   end
 
-  describe "#exchange_xmpp_contacts" do
-    include ActiveJob::TestHelper
-
-    let(:inviter) { create :user, cn: "willherschel", ou: "kosmos.org" }
-    let(:invitation) { create :invitation, user: inviter }
-    let(:service) { CreateAccount.new(
-      username: 'isaacnewton',
-      email: 'isaacnewton@example.com',
-      password: 'bright-ideas-in-autumn',
-      invitation: invitation
-    )}
-
-    it "enqueues a job to exchange XMPP contacts between inviter and invitee" do
-      service.send(:exchange_xmpp_contacts)
-
-      expect(enqueued_jobs.size).to eq(1)
-
-      args = enqueued_jobs.first['arguments']
-      expect(args[0]['_aj_globalid']).to match('gid://akkounts/User')
-      expect(args[1]).to eq('isaacnewton')
-      expect(args[2]).to eq('kosmos.org')
-    end
-
-    after do
-      clear_enqueued_jobs
-    end
-  end
-
   describe "#create_lndhub_account" do
     include ActiveJob::TestHelper