enhanced gradebook lock down query param routing

currently the new enhanced individual gradebook is able to be accessed
with the FF off if the user knows to navigate to the gradebook url with
the query param ?version=individual_enhanced. This commit adds a check
on the backend during the routing that will now direct the user to the
traditional gradebook grid if the FF is off.

closes EVAL-3419

flag=individual_gradebook_enhancements

test plan:
- navigate to /courses/<course_id>/gradebook?version=individual_enhanced
  and verify that you are directed to traditional gradebook

Change-Id: Ief0c905ffd919a0ea87a3c7643a07fff3ab9ac67
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/325291
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
Reviewed-by: Aaron Shafovaloff <ashafovaloff@instructure.com>
QA-Review: Rohan Chugh <rohan.chugh@instructure.com>
Product-Review: Ravi Koll <ravi.koll@instructure.com>

app/controllers/gradebooks_controller.rb

@@ -320,7 +320,8 @@ class GradebooksController < ApplicationController
         return
       end
 
-      if gradebook_version == "individual_enhanced"
+      individual_enhanced_enabled = @context.root_account.feature_enabled?(:individual_gradebook_enhancements)
+      if gradebook_version == "individual_enhanced" && individual_enhanced_enabled
         show_enhanced_individual_gradebook
       elsif ["srgb", "individual"].include?(gradebook_version)
         show_individual_gradebook

config/feature_flags/apogee_release_flags.yml

@@ -217,7 +217,7 @@ individual_gradebook_enhancements:
     to Individual Gradebook
   environments:
     ci:
-      state: on # enable for automated testings builds and local testing
+      state: allowed_on # enable for automated testings builds and local testing
     development:
       state: allowed_on # enable for local development
 hide_zero_point_quizzes_option:

spec/controllers/gradebooks_controller_spec.rb

@@ -1021,6 +1021,20 @@ describe GradebooksController do
         expect(response).to render_template("gradebooks/gradebook")
       end
 
+      it "renders enhanced individual gradebook when individual_enhanced & individual_gradebook_enhancements is enabled" do
+        @course.root_account.enable_feature!(:individual_gradebook_enhancements)
+        @admin.set_preference(:gradebook_version, "individual_enhanced")
+        get "show", params: { course_id: @course.id }
+        expect(response).to render_template("layouts/application")
+      end
+
+      it "renders traditional gradebook when individual_gradebook_enhancements is disabled" do
+        @course.root_account.disable_feature!(:individual_gradebook_enhancements)
+        @admin.set_preference(:gradebook_version, "individual_enhanced")
+        get "show", params: { course_id: @course.id }
+        expect(response).to render_template("gradebooks/gradebook")
+      end
+
       describe "score to ungraded" do
         before do
           options = Gradebook::ApplyScoreToUngradedSubmissions::Options.new(