Never schedule the hi segment for a lo participant. #3998.

And vice-versa. Among other things, this ensures that lo participants
with extended data collection will not get scheduled onto the hi
postnatal segment.
This is now redundant. #3998.

Since a hi segment is no longer treated as an option for a lo
participant, this condition will never be true and so we can eliminate
it.
Skip all informed consent events. #4010.

There are several informed consent events in the template. Selecting
one to schedule would require knowledge of the actual consent(s)
executed in the event. This has several problems:

* It is frequently not possible to find a consent record for a
  particular consent event due to the poor quality of much imported
  data.
* It would require additional engineering effort to make the consent
  details visible to the sync.
* It would only work for consent events where the consent has already
  been executed. The case where it would be useful to schedule a
  consent segment during import is when the consent is still pending.

(See also #1818.)

Before this change, any informed consent events would be logged as
ambiguous. This is fine as far as it goes -- the sync still completes
-- but it litters the log with "expected" errors. Since there are a
lot of informed consent events in any given schedule, it can obscure
actual problems.

Skipping the informed consent events completely avoids logging about
them without changing the practical effects of using the PSC sync.
Remove multiple refs to same string literal. #4010.
Merge pull request #152 from NUBIC/3998-psc_no_hi_for_lo

PSC sync: do not schedule hi events for lo participants (#3998, #4010)