toggle star icon state when starred via cog menu in inbox

fixes CNVS-27745

test plan
- in conversations inbox, toggle starred status on a conversation
 via the cog menu
- ensure that the title of the conversation's star icon on the
 left sidebar reads "Unstar" or "Star" as appropriate. read the
 title either with a screenreader or by hovering the mouse over
 the icon

Change-Id: I4d2f2d42ff5b0d9de003e8fb3f5036a64d337504
Reviewed-on: https://gerrit.instructure.com/74066
Tested-by: Jenkins
Reviewed-by: Steven Burnett <sburnett@instructure.com>
QA-Review: Deepeeca Soundarrajan <dsoundarrajan@instructure.com>
Product-Review: Joel Hough <joel@instructure.com>

app/coffeescripts/views/conversations/MessageView.coffee

@@ -33,7 +33,7 @@ define [
       @attachModel()
 
     attachModel: ->
-      @model.on('change:starred', => @$starBtn.toggleClass('active'))
+      @model.on('change:starred', @setStarBtnChecked)
       @model.on('change:workflow_state', => @$readBtn.toggleClass('read', @model.get('workflow_state') isnt 'unread'))
       @model.on('change:selected', (m) => @$el.toggleClass('active', m.get('selected')))
 
@@ -55,13 +55,17 @@ define [
     deselect: (modifier) ->
       @model.set('selected', false) if modifier
 
+    setStarBtnChecked: =>
+      @$starBtn.attr
+        'aria-checked': @model.starred()
+        title: if @model.starred() then @messages.unstar else @messages.star
+      @$starBtn.toggleClass('active', @model.starred())
+
     toggleStar: (e) ->
       e.preventDefault()
       @model.toggleStarred()
       @model.save()
-      @$starBtn.attr
+      @setStarBtnChecked()
-        'aria-checked': @model.starred()
-        title: if @model.starred() then @messages.unstar else @messages.star
 
     toggleRead: (e) ->
       e.preventDefault()

spec/selenium/conversations/conversations_spec.rb

@@ -431,6 +431,7 @@ describe "conversations new" do
       wait_for_ajaximations
       click_star_toggle_menu_item
       expect(f('.active', unstarred_elt)).to be_present
+      expect(f('.star-btn', unstarred_elt)['aria-checked']).to eq "true"
       run_progress_job
       expect(@conv_unstarred.reload.starred).to be_truthy
     end