Direction queries for HGV profile include `hazmat` profile parameter

Directions queries to the HGV profile specify the `hazmat = false` parameter. The flag should probably not be included in the query unless set by the user to `hazmat = true`, otherwise discrepancies described in https://github.com/GIScience/openrouteservice/issues/2066 are observed.

Start by tracing where the HGV directions query is assembled and how the hazmat option is serialized. The change is complete when hazmat=false is omitted, hazmat=true remains included, and the resulting queries can be checked against the discrepancy described in issue 2066.

Written by the indexing model from the issue text.