Removed the constraints / constraints set in the diagram builder since we do not need them anymore. As a consequence, the associated methods need to be removed as well.
JUnit tests for diagram builder updates since the method canAdd is removed from it.
JUnit tests for all usage scenarios are updated as well since it used to rely on the usage of canAdd method.
There are several things done in this PR:
canAdd
is removed from it.canAdd
method.