FIX: Support for single use invite links (#11719)

The "invite link" checked if the number of uses was greater than 1. This
is not always true as single use invite links are perfectly valid.

spec/models/invite_spec.rb

@@ -197,6 +197,12 @@ describe Invite do
     context 'invite links' do
       let(:inviter) { Fabricate(:user) }
 
+      it 'with single use can exist' do
+        Invite.generate_multiple_use_invite_link(invited_by: inviter, max_redemptions_allowed: 1)
+        invite_link = Invite.last
+        expect(invite_link.is_invite_link?).to eq(true)
+      end
+
       it "has sane defaults" do
         Invite.generate_multiple_use_invite_link(invited_by: inviter)
         invite_link = Invite.last