FIX: use input event instead of change event

Author: angusmcleod

assets/javascripts/discourse/templates/admin-wizards-manager.hbs

@@ -15,7 +15,7 @@
       id="file-upload"
       type="file"
       accept="application/json"
-      change=(action "setFile")}}
+      input=(action "setFile")}}
     {{d-button
       id="upload-button"
       label="admin.wizard.manager.upload"