TableItemView was including a prototypeAttrs override listing the

template member, but this is already included in the parent class one,

and we automerge those. Unfortunately, having this override seems to

have triggered a different bug in spina's automerge where we were losing

the other items. This was causing us to not have action handlers for the

extension list, breaking the "Enable" and "Disable" actions.

Saw that I was able to enable and disable extensions.