remove some extra text in assignment created sms

fixes COMMS-1921

Test Plan:
- as a student add a sms communication channel
- set all sms notifications to on
- as a teacher in the course the studnet is in
  create an assignment
- go to users/<user_id>/messages and notice the content
  matches the spreadsheet design

Change-Id: I07c1180a863dc69be76c97615cd1a0519f7d7351
Reviewed-on: https://gerrit.instructure.com/184567
Tested-by: Jenkins
Reviewed-by: Ryan Norton <rnorton@instructure.com>
QA-Review: Ryan Norton <rnorton@instructure.com>
Product-Review: Steven Burnett <sburnett@instructure.com>

app/messages/assignment_created.sms.erb

@@ -1,11 +1,8 @@
 <%= I18n.t("New assignment for %{course_name}", :course_name => asset.context.name) %>
-<%= asset.title %>
-
 <%
   multiple_dates_text = I18n.t("due: Multiple Dates")
   display_text = I18n.t("due: No Due Date")
 %>
-
 <% if asset.multiple_due_dates_apply_to?(user) %>
   <% display_text = multiple_dates_text %>
 <% elsif asset.due_at %>
@@ -19,7 +16,4 @@
     <% end %>
   <% end %>
 <% end %>
-
 <%= display_text %>
-
-<%= I18n.t("More info at %{course_name}", :course_name => HostUrl.context_host(asset.context)) %>