Message templates - installer doesn't install a copy with is_reserved=1

Normally message templates have two copies each in the db, one with is_default=1 and is_reserved=0, which actually means "this is the one in use", and another with is_reserved=1 and is_default=0, which actually means "the default version". This is how it supports the "revert to default" link. Since there is no is_reserved=1 copy, there isn't a link to revert to default.

It's a simple template that's easy to manually recreate, but the extension could install the reserved copy here at the same time as the other one.