Trip mode choice for trips on at-work subtours

[jpn--]

trafficstars

as reported by @jfdman

Trip mode choice for trips on at-work subtours aren’t being estimated.

[AndrewTheTM]

I ended up getting around this by commenting out a few lines (not sure that's the optimal approach, but I was able to get my work done):

https://github.com/ActivitySim/activitysim/blob/1e4ffc5cdd745c183b2b50385e457c8cfaa6c18d/activitysim/estimation/larch/mode_choice.py#L53 and the following line

https://github.com/ActivitySim/activitysim/blob/1e4ffc5cdd745c183b2b50385e457c8cfaa6c18d/activitysim/estimation/larch/mode_choice.py#L89

https://github.com/ActivitySim/activitysim/blob/1e4ffc5cdd745c183b2b50385e457c8cfaa6c18d/activitysim/estimation/larch/mode_choice.py#L93 and the following three

I'll note that this is not thoroughly tested and may cause issues in tour mode choice (since at-work is not part of that group).