Fixes issue encountered when cms worker updates grades:

Grades: SGF.update
...
Cannot grade student 2 in course course-v1:...  because of exception: 'Settings' object has no attribute 'GENERATE_PROFILE_SCORES'

(cherry picked from commit e0ae8f49a64c3148d446d7e535eca26016dd17d1)

cms/envs/common.py

@@ -128,6 +128,9 @@ from lms.envs.common import (
     CONTACT_EMAIL,
 
     DISABLE_ACCOUNT_ACTIVATION_REQUIREMENT_SWITCH,
+
+    GENERATE_PROFILE_SCORES,
+
     # Video Image settings
     VIDEO_IMAGE_SETTINGS,
     VIDEO_TRANSCRIPTS_SETTINGS,