Import of DataModel hangs on validation of invalid EnumerationValues

[joe-crawford]

Description

When importing a DataModel DM with the following structure:

DM
  - DC1
    - DC1a
      - DE - type EnumerationType A
  - DC2
    - DC2a
      - DE 

When EnumerationType A has invalid EnumerationValues, e.g. including a @ in an EnumerationValue key, importing a DataModel hangs on importing a DataModel.

However with the same EnumerationType A, the following model validation proceeds and returns the correct error message:

DM
  - DC1
    - DC1a
      - DE - type EnumerationType A

i.e. the error doesn't occur with one root DataClass.

Seen on latest of mdm-application-build with DataModel from SDE warehouse.