Ensure LDAP users can get activated with any registration setting

LDAP users get an auth_source_id attached to them during registration,
since they are effectively not self-registrating in the system,
the register service should allow them with any self_registration setting.

At the same time, the refactoring ensure that even an LDAP user that logs in for the first
time is being redirected to home to get the welcome tour.

app/services/users/register_user_service.rb

@@ -38,6 +38,7 @@ module Users
     def call
       %i[
         register_invited_user
+        register_ldap_user
         ensure_registration_allowed!
         ensure_user_limit_not_reached!
         register_by_email_activation
@@ -86,6 +87,19 @@ module Users
       end
     end
 
+    ##
+    # Try to register a user with an auth source connection
+    # bypassing regular restrictions
+    def register_ldap_user
+      return unless user.auth_source_id.present?
+
+      user.activate
+
+      with_saved_user_result(success_message: I18n.t(:notice_account_registered_and_logged_in)) do
+        Rails.logger.info { "User #{user.login} was successfully activated after invitation." }
+      end
+    end
+
     def register_by_email_activation
       return unless Setting::SelfRegistration.by_email?
 

spec/controllers/account_controller_spec.rb

@@ -879,7 +879,7 @@ describe AccountController, type: :controller do
                    mail: 'foo@bar.com'
                  }
                }
-          expect(response).to redirect_to '/my/account'
+          expect(response).to redirect_to home_path(first_time_user: true)
 
           user = User.find_by_login('foo')
 

spec/services/users/register_user_service_spec.rb

@@ -59,6 +59,24 @@ describe Users::RegisterUserService do
     end
   end
 
+  describe '#register_ldap_user' do
+    it 'tries to activate that user regardless of settings' do
+      with_all_registration_options do |_type|
+        user = User.new(status: Principal::STATUSES[:registered])
+        instance = described_class.new(user)
+
+        allow(user).to receive(:auth_source_id).and_return 1234
+        expect(user).to receive(:activate)
+        expect(user).to receive(:save).and_return true
+
+        call = instance.call
+        expect(call).to be_success
+        expect(call.result).to eq user
+        expect(call.message).to eq I18n.t(:notice_account_registered_and_logged_in)
+      end
+    end
+  end
+
   describe '#ensure_registration_allowed!' do
     it 'returns an error for disabled' do
       allow(Setting).to receive(:self_registration).and_return(0)