feat: API to allow agents to delete a message (#1353)

app/controllers/api/v1/accounts/conversations/messages_controller.rb

@@ -11,9 +11,24 @@ class Api::V1::Accounts::Conversations::MessagesController < Api::V1::Accounts::
     render_could_not_create_error(e.message)
   end
 
+  def destroy
+    ActiveRecord::Base.transaction do
+      message.update!(content: I18n.t('conversations.messages.deleted'), deleted: true)
+      message.attachments.destroy_all
+    end
+  end
+
   private
 
+  def message
+    @message ||= @conversation.messages.find(permitted_params[:id])
+  end
+
   def message_finder
     @message_finder ||= MessageFinder.new(@conversation, params)
   end
+
+  def permitted_params
+    params.permit(:id)
+  end
 end