Fix: allow staff and direct message enabled groups to create personal chats

plugins/chat/app/serializers/chat/chatable_user_serializer.rb

@@ -5,7 +5,7 @@ class ChatableUserSerializer < UserWithCustomFieldsSerializer
     attributes :can_chat, :has_chat_enabled
 
     def can_chat
-      SiteSetting.chat_enabled && object.guardian.can_chat? && object.guardian.can_direct_message?
+      SiteSetting.chat_enabled && object.guardian.can_chat? && scope.can_create_direct_message?
     end
 
     def has_chat_enabled

plugins/chat/spec/serializer/chat/chatable_user_serializer_spec.rb

@@ -54,4 +54,20 @@
       expect(serializer.as_json[:can_chat]).to eq(false)
     end
   end
+
+  context "when staff creates direct messages" do
+    fab!(:admin)
+    subject(:serializer) { described_class.new(user, scope: Guardian.new(admin), root: false) }
+
+    before { SiteSetting.direct_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_4] }
+
+    it "can chat" do
+      expect(serializer.as_json[:can_chat]).to eq(true)
+    end
+
+    it "can't chat if user has chat disabled" do
+      user.user_option.update!(chat_enabled: false)
+      expect(serializer.as_json[:has_chat_enabled]).to eq(false)
+    end
+  end
 end