fix: Fix proctored exam display in learning_sequences admin.

I had the wrong attribute before this commit, and Django Admin let
me get away with it because it doesn't explode when you try to grab
relations that aren't there–it just quietly returns None in some of
those cases.

openedx/core/djangoapps/content/learning_sequences/admin.py

@@ -52,7 +52,7 @@ class CourseSectionSequenceInline(admin.TabularInline):
     fields = (
         'title',
         'is_time_limited',
-        'is_proctored_exam',
+        'is_proctored_enabled',
         'is_practice_exam',
         'accessible_after_due',
         'visible_to_staff_only',
@@ -61,7 +61,7 @@ class CourseSectionSequenceInline(admin.TabularInline):
     readonly_fields = (
         'title',
         'is_time_limited',
-        'is_proctored_exam',
+        'is_proctored_enabled',
         'is_practice_exam',
         'accessible_after_due',
         'visible_to_staff_only',
@@ -100,10 +100,10 @@ class CourseSectionSequenceInline(admin.TabularInline):
     is_time_limited.boolean = True
     is_time_limited.short_description = "Timed Exam"
 
-    def is_proctored_exam(self, cs_seq):
-        return cs_seq.exam.is_proctored_exam
-    is_proctored_exam.boolean = True
-    is_proctored_exam.short_description = "Proctored Exam"
+    def is_proctored_enabled(self, cs_seq):
+        return cs_seq.exam.is_proctored_enabled
+    is_proctored_enabled.boolean = True
+    is_proctored_enabled.short_description = "Proctored Exam"
 
     def is_practice_exam(self, cs_seq):
         return cs_seq.exam.is_practice_exam