chore: Message API improvements (#2396)

Co-authored-by: Pranav Raj S <pranav@chatwoot.com>

spec/controllers/api/v1/accounts/conversations/messages_controller_spec.rb

@@ -31,6 +31,23 @@ RSpec.describe 'Conversation Messages API', type: :request do
         expect(conversation.messages.first.content).to eq(params[:content])
       end
 
+      it 'creates an outgoing message with a specific bot sender' do
+        agent_bot = create(:agent_bot)
+        time_stamp = Time.now.utc.to_s
+        params = { content: 'test-message', external_created_at: time_stamp, sender_type: 'AgentBot', sender_id: agent_bot.id }
+
+        post api_v1_account_conversation_messages_url(account_id: account.id, conversation_id: conversation.display_id),
+             params: params,
+             headers: agent.create_new_auth_token,
+             as: :json
+
+        expect(response).to have_http_status(:success)
+        response_data = JSON.parse(response.body)
+        expect(response_data['content_attributes']['external_created_at']).to eq time_stamp
+        expect(conversation.messages.count).to eq(1)
+        expect(conversation.messages.last.sender_id).to eq(agent_bot.id)
+      end
+
       it 'creates a new outgoing message with attachment' do
         file = fixture_file_upload(Rails.root.join('spec/assets/avatar.png'), 'image/png')
         params = { content: 'test-message', attachments: [file] }