(maint) fix template string layout

Prior to this change, the strings for the buttons and checkboxes in the
dummy app were broken into multiple independent strings. This caused the
text matcher to not find the strings, and as a result the tests would fail.

Concatenating these strings again resolved the issue.

Author: jonathannewman

tests/dummy/app/templates/dynamic-tabs.hbs

@@ -32,9 +32,7 @@
             >
               <span aria-hidden="true">&times;</span>
             </button>
-
-            Item
-            {{item.index}}
+            Item {{item.index}}
           </tablist.tab>
         </li>
       {{/each}}
@@ -68,9 +66,7 @@
     type="button"
     {{on "click" this.removeSelected}}
   >
-    Remove
-    {{this.checkedItems.length}}
-    Item(s)
+    Remove {{this.checkedItems.length}} Item(s)
   </button>
 
   <ul class="list-unstyled">
@@ -83,8 +79,7 @@
               checked={{item.checked}}
               {{on "input" (fn this.toggleItemCheckedState item)}}
             />
-            Item
-            {{item.index}}
+            Item {{item.index}}
           </label>
         </div>
       </li>