Update emailSelection export and usage to Evan-recommended "module style" syntax

src/components/BulkActionBar.vue

@@ -30,7 +30,7 @@
 
   export default {
     setup({emails}){
-      let { emailSelection } = useEmailSelection();
+      let emailSelection = useEmailSelection();
 
       let numberSelected = computed(() => {
         return emailSelection.emails.size;

src/components/MailScreen.vue

@@ -27,12 +27,11 @@
       let response = await axios.get('http://localhost:3000/emails');
       let emails = response.data;
       let selectedScreen = 'archive';
-      let {emailSelection} = useEmailSelection();
 
       return { 
         emails,
         selectedScreen,
-        emailSelection
+        emailSelection: useEmailSelection()
       }
     },
     components: {

src/components/MailTable.vue

@@ -35,13 +35,10 @@
 
   export default {
     async setup(){
-      let openedEmail = null;
-      let { emailSelection } = useEmailSelection();
-
       return {
         format,
-        openedEmail,
-        emailSelection
+        openedEmail: null,
+        emailSelection: useEmailSelection()
       }
     },
     components: {