Revert "Fix app service start (regression)"

[kebson01]

Reverts #428

[davidxw]

@kebson01 I think I rolled back this change because when the site doesn't render properly when not started with "next start" and when deployed via azd (which sets SCM_DO_BUILD_DURING_DEPLOYMENT to true). In our sample pipeline deployments we build locally, set SCM_DO_BUILD_DURING_DEPLOYMENT to false, push a static site, and run as a node application. We've assumed that the majority of users of this repo will be using azd so we've made that the default start command in the templates compatible with that.