Set transit-group-priority for requests without via points

[flaktack]

Summary

Currently transitGroupPriority is turned off for non-via requests, due to hasPassThroughOnly() being true for a request without any via locations:

 request.getViaLocations().stream().allMatch(ViaLocation::isPassThroughLocation)

This updates hasPassThroughOnly() and hasViaLocationsOnly() to also check that the request is actually a isViaSearch().

Unit tests

New tests are added to verify that transitPriorityCalculator() is set for non-via and visit-via searches.

[t2gran]

Thank you for reporting and fixing this. While reviewing I noticed that there was a regression for the relaxCostAtDestination witch should only be allowed if none of the other features is used. I made a fix and found a minor bug in addition. I added a new parameterized unit-test to test all combinations of via-visit, via-pass-through, transit-priority-group and relax-cost-at-destination.

If you can, cherry-pick or copy my commit into your PR(or I can create a new PR). I made my fix on top of your fix: 7cdce4a branch

[flaktack]

I would prefer a separate PR to simplify the review process.

[t2gran]

But there is a bug in the fix you made - it is minor so I can do it in a separate PR - but the relaxCostAtDestination does not work.

[t2gran]

I will create a separate PR for it - it does not matter to me.