Remove use of read_cached_programs switch

The read_cached_programs switch was used to control the release of changes for reading programs exclusively from the cache. With those changes stable, the switch is no longer necessary.

LEARNER-382

lms/envs/bok_choy.env.json

@@ -84,6 +84,7 @@
         "ALLOW_AUTOMATED_SIGNUPS": true,
         "AUTOMATIC_AUTH_FOR_TESTING": true,
         "MODE_CREATION_FOR_TESTING": true,
+        "EXPOSE_CACHE_PROGRAMS_ENDPOINT": true,
         "AUTOMATIC_VERIFY_STUDENT_IDENTITY_FOR_TESTING": true,
         "ENABLE_COURSE_DISCOVERY": true,
         "ENABLE_SPECIAL_EXAMS": true,

lms/envs/common.py

@@ -290,6 +290,10 @@ FEATURES = {
     # For easily adding modes to courses during acceptance testing
     'MODE_CREATION_FOR_TESTING': False,
 
+    # For caching programs in contexts where the LMS can only
+    # be reached over HTTP.
+    'EXPOSE_CACHE_PROGRAMS_ENDPOINT': False,
+
     # Courseware search feature
     'ENABLE_COURSEWARE_SEARCH': False,