Fix: Creating flags on review apps attempting to notify our flags Dis…

…cord channel

Because:
* When creating a flag on a review app it was returning a 500 response because the discord notifier isn't configured.
* We don't want testing flags on review apps to create noise in our Discord channel.

This commit:
* Do not run the discord notifier service if we're in the development environment or staging (review apps).
* Removes the json responses for creating flags, those were used from the removed react implementation of the flag form.

app/controllers/project_submissions/flags_controller.rb

@@ -6,18 +6,16 @@ def new
     @flag = @project_submission.flags.new
   end
 
-  def create # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
+  def create
     @flag = @project_submission.flags.new(flag_params)
 
     respond_to do |format|
       if @flag.save
         notify_discord_admins
 
         format.html { redirect_to lesson_path(@project_submission.lesson) }
-        format.json { render json: @flag, status: :created }
         format.turbo_stream { flash.now[:notice] = 'Thank you! your report has been submitted.' }
       else
-        format.json { render json: { error: 'Unable to flag project submission' }, status: :unprocessable_entity }
         format.html { render :new, status: :unprocessable_entity }
       end
     end
@@ -34,10 +32,14 @@ def flag_params
   end
 
   def notify_discord_admins
-    return unless Rails.env.production?
+    return unless discord_notifications_enabled?
 
     DiscordNotifier.notify(
       Notifications::FlagSubmission.new(@flag)
     )
   end
+
+  def discord_notifications_enabled?
+    Rails.env.production? && ENV['STAGING'].blank?
+  end
 end