recheck submissions are still missing in missing_policy_applicator

recheck this value right before the missing policy is applied
to make sure users have not submitted while the applicator was running

closes EVAL-3279
flag=none

test plan:
- tests pass

Change-Id: I40648825b36bdc99821fe2fa5fc1f152776a04ae
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/336292
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Drake Harper <drake.harper@instructure.com>
Reviewed-by: Kai Bjorkman <kbjorkman@instructure.com>
QA-Review: Spencer Olson <solson@instructure.com>
Product-Review: Cameron Ray <cameron.ray@instructure.com>

lib/missing_policy_applicator.rb

@@ -56,7 +56,7 @@ class MissingPolicyApplicator
 
     GuardRail.activate(:primary) do
       plucked_submissions = submissions.pluck(:user_id, :id, :course_id)
-      submissions = Submission.active.where(id: submissions)
+      submissions = Submission.active.missing.where(id: submissions)
 
       submissions.update_all(
         score:,

spec/lib/missing_policy_applicator_spec.rb

@@ -451,5 +451,19 @@ describe MissingPolicyApplicator do
         end
       end
     end
+
+    describe "apply missing deduction" do
+      it "double checks and doesn't update submissions if they have been submitted" do
+        late_policy_missing_enabled
+        create_recent_assignment
+        submission = @course.submissions.first
+        submission.update_columns(score: nil, grade: nil, workflow_state: "submitted", submission_type: "online_text_entry")
+        assignment = submission.assignment
+
+        applicator.send(:apply_missing_deduction, assignment, [submission])
+
+        expect(submission.reload.score).to be_nil
+      end
+    end
   end
 end