SW-6658 - Fix backend property module. The assignment grid used another model, so the internalId property collided.
SW-6658 - Disable drop function in the global group grid. Fix group moving within the set assignment grid.
Merge pull request #455 in SW/shopware from bugfix/master/sw-6658-fix-property-module to master

* commit '6bdd461900004887ad29f5f5fd5e2523e43c07f7':
  SW-6658 - Disable drop function in the global group grid. Fix group moving within the set assignment grid.
  SW-6658 - Fix backend property module. The assignment grid used another model, so the internalId property collided.