fix: do not instantiate the PartitionService during XBlock validation…

… in Studio

xmodule/modulestore/split_mongo/split.py

@@ -3287,7 +3287,11 @@ def create_runtime(self, course_entry, lazy):
         Create the proper runtime for this course
         """
         services = self.services
-        services["partitions"] = PartitionService(course_entry.course_key)
+        # Only the CourseBlock can have user partitions. Therefore, creating the PartitionService with the library key
+        # instead of the course key does not work. The XBlock validation in Studio fails with the following message:
+        # "This component's access settings refer to deleted or invalid group configurations.".
+        if not isinstance(course_entry.course_key, LibraryLocator):
+            services["partitions"] = PartitionService(course_entry.course_key)
 
         return CachingDescriptorSystem(
             modulestore=self,