fix: streak celebration feature should require progress milestones (#26922)

In commit 9b37e7d0, the logic of
`streak_celebration_is_active` was accidentally
changed such that it no longer checks the
Progress Milestones waffle flag.
This commit fixes that.

Note: This also adds in a transitive check to
`courseware_mfe_is_active`,
which makes sense for Streak Celebration
and should not have any functional impact.

lms/djangoapps/courseware/toggles.py

@@ -205,6 +205,6 @@ def courseware_mfe_progress_milestones_are_active(course_key):
 
 def streak_celebration_is_active(course_key):
     return (
-        courseware_mfe_is_active(course_key) and
+        courseware_mfe_progress_milestones_are_active(course_key) and
         COURSEWARE_MICROFRONTEND_PROGRESS_MILESTONES_STREAK_CELEBRATION.is_enabled(course_key)
     )