add bcc completed submission param

app/controllers/api/submissions_controller.rb

@@ -136,7 +136,7 @@ module Api
 
       params.permit(
         key => [
-          [:send_email, :send_sms, {
+          [:send_email, :send_sms, :bcc_completed, {
             message: %i[subject body],
             submitters: [[:send_email, :send_sms, :uuid, :name, :email, :role,
                           :completed, :phone, :application_key,

app/jobs/process_submitter_completion_job.rb

@@ -28,7 +28,8 @@ class ProcessSubmitterCompletionJob < ApplicationJob
        submitter.submission.preferences['send_email'] != false
       SubmitterMailer.completed_email(submitter, user).deliver_later!
 
-      bcc = submitter.submission.template.account.account_configs
+      bcc = submitter.submission.preferences['bcc_completed'].presence ||
+            submitter.submission.template.account.account_configs
                      .find_by(key: AccountConfig::BCC_EMAILS)&.value.presence
 
       SubmitterMailer.completed_email(submitter, user, to: bcc).deliver_later! if bcc