fix(mps-model-adapters): don't reject illegal concept descriptors

MPS might still be able to work with them.

Author: mhuster23

mps-model-adapters/src/main/kotlin/org/modelix/model/mpsadapters/MPSLanguageRepository.kt

@@ -20,7 +20,6 @@ import jetbrains.mps.smodel.adapter.ids.SConceptId
 import jetbrains.mps.smodel.adapter.structure.MetaAdapterFactory
 import jetbrains.mps.smodel.language.ConceptRegistry
 import jetbrains.mps.smodel.language.LanguageRegistry
-import jetbrains.mps.smodel.runtime.illegal.IllegalConceptDescriptor
 import org.jetbrains.mps.openapi.language.SAbstractConcept
 import org.jetbrains.mps.openapi.module.SRepository
 import org.modelix.model.api.IConcept
@@ -39,8 +38,6 @@ data class MPSLanguageRepository(private val repository: SRepository) : ILanguag
 
         val conceptDescriptor = ConceptRegistry.getInstance().getConceptDescriptor(conceptId)
 
-        if (conceptDescriptor is IllegalConceptDescriptor) return null
-
         return MPSConcept(MetaAdapterFactory.getAbstractConcept(conceptDescriptor))
     }