Missing media in SegmentModelAdmin

[aweakley]

In our segment admin view at /admin/wagtail_personalisation/segment/edit/1/ the page chooser in the Visit Count Rule does not pop up the modal because wagtailadmin/js/page-chooser.js and wagtailadmin/js/page-chooser-modal.js are missing from the media.
I've fixed it by adding those files to SegmentModelAdmin.form_view_extra_js, but is there a better way?

[jberghoef]

The issue seems to have been caused by overriding the extra_js template block. #195 should fix this.

[aweakley]

That didn't fix it for me I'm afraid. I've pulled d9ef74c and I'm getting the same behaviour.