fix LR sourcing with a PR

* use the correct API version in the wizard:
  the code would use self.pool.get which returns an old-API model
  and then use it through the new API

* add a yaml test for this sourcing flow (long because we need to manually
  process the whole PR)

* fix various isssues with new API use:
  - cannot write on a recorset with > 1 records
  - confusions with bits expecting records / ids