Enhancement: ability to send out an email without summary #1048 (#1049)

Right now as part of conversation continuity, we are using the
ConversationReplyMailer which sends a summary of messages including
the incoming messages when an agent replies. Ideally, we want
to send only the reply of that agent and not a summary when
Conversation continuity is enabled. Added the functionality
to send the reply email without summary. Added required unit
tests to cover the changes.

ref: #1048

spec/workers/conversation_reply_email_worker_spec.rb

@@ -5,6 +5,7 @@ RSpec.describe ConversationReplyEmailWorker, type: :worker do
   let(:perform_at) { (Time.zone.today + 6.hours).to_datetime }
   let(:scheduled_job) { described_class.perform_at(perform_at, 1, Time.zone.now) }
   let(:conversation) { build(:conversation, display_id: nil) }
+  let(:message) { build(:message, conversation: conversation, content_type: 'incoming_email', inbox: conversation.inbox) }
 
   describe 'testing ConversationSummaryEmailWorker' do
     before do
@@ -12,6 +13,7 @@ RSpec.describe ConversationReplyEmailWorker, type: :worker do
       allow(Conversation).to receive(:find).and_return(conversation)
       mailer = double
       allow(ConversationReplyMailer).to receive(:reply_with_summary).and_return(mailer)
+      allow(ConversationReplyMailer).to receive(:reply_without_summary).and_return(mailer)
       allow(mailer).to receive(:deliver_later).and_return(true)
     end
 
@@ -28,10 +30,16 @@ RSpec.describe ConversationReplyEmailWorker, type: :worker do
     end
 
     context 'with actions performed by the worker' do
-      it 'calls ConversationSummaryMailer' do
+      it 'calls ConversationSummaryMailer#reply_with_summary when last incoming message was not email' do
         described_class.new.perform(1, Time.zone.now)
         expect(ConversationReplyMailer).to have_received(:reply_with_summary)
       end
+
+      it 'calls ConversationSummaryMailer#reply_without_summary when last incoming message was from email' do
+        message.save
+        described_class.new.perform(1, Time.zone.now)
+        expect(ConversationReplyMailer).to have_received(:reply_without_summary)
+      end
     end
   end
 end