refactor: Output window: markAsSent checked by default pcsg/buero#220

bin/backend/controls/OutputDialog.html

@@ -61,7 +61,7 @@
                         {{labelMarkAsSent}}
                     </span>
                         <div class="field-container-field">
-                            <input type="checkbox" name="mark_as_sent"/>
+                            <input type="checkbox" name="mark_as_sent" checked/>
                         </div>
                     </label>
                     <div class="field-container-item-desc">