Use settings on MailPoet object rather than on Window

[MAILPOET-3763]

assets/js/src/mailpoet.js

@@ -24,6 +24,7 @@ var MailPoet = {
   wpWeekStartsOn: window.mailpoet_wp_week_starts_on,
   subscribersCountsCacheCreatedAt: window.mailpoet_subscribers_counts_cache_created_at,
   getShortcodeLinks: () => (window.mailpoet_shortcode_links ? window.mailpoet_shortcode_links : []),
+  settings: window.settings,
 };
 
 // Expose MailPoet globally

assets/js/src/newsletters/send/re_engagement.tsx

@@ -1,19 +1,11 @@
 import React from 'react';
-import MailPoet from 'mailpoet';
 import { assoc, find, map } from 'lodash/fp';
 
+import MailPoet from 'mailpoet';
 import { Scheduling } from '../types/re_engagement/scheduling';
 import GATrackingField from './ga_tracking';
 import SenderField from './sender_address_field';
 
-interface ReengagementWindow extends Window {
-  settings: {
-    deactivate_subscriber_after_inactive_days: string;
-  }
-}
-
-declare let window: ReengagementWindow;
-
 interface onValueChangeParam {
   target: {
     name: string,
@@ -40,7 +32,7 @@ function FormReEngagementScheduling(props: Props): JSX.Element {
       afterTimeNumber={props.item.options.afterTimeNumber.toString()}
       afterTimeType={props.item.options.afterTimeType}
       inactiveSubscribersPeriod={
-        Number(window.settings.deactivate_subscriber_after_inactive_days)
+        Number(MailPoet.settings.deactivate_subscriber_after_inactive_days)
       }
       updateAfterTimeNumber={(value) => {
         props.onValueChange({

assets/js/src/newsletters/types/re_engagement/re_engagement.tsx

@@ -11,18 +11,10 @@ import APIErrorsNotice from 'notices/api_errors_notice';
 import { Scheduling } from './scheduling';
 import ListingHeadingStepsRoute from '../../listings/heading_steps_route';
 
-interface ReengagementWindow extends Window {
-  settings: {
-    deactivate_subscriber_after_inactive_days: string;
-  }
-}
-
-declare let window: ReengagementWindow;
-
 export function NewsletterTypeReEngagement(): JSX.Element {
   const [options, setOptions] = useState({
     afterTimeNumber: (
-      (Number(window.settings.deactivate_subscriber_after_inactive_days) / 30) - 1
+      (Number(MailPoet.settings.deactivate_subscriber_after_inactive_days) / 30) - 1
     ).toString(),
     afterTimeType: 'months',
   });
@@ -66,7 +58,7 @@ export function NewsletterTypeReEngagement(): JSX.Element {
           afterTimeNumber={options.afterTimeNumber}
           afterTimeType={options.afterTimeType}
           inactiveSubscribersPeriod={
-            Number(window.settings.deactivate_subscriber_after_inactive_days)
+            Number(MailPoet.settings.deactivate_subscriber_after_inactive_days)
           }
           updateAfterTimeNumber={compose([setOptions, assoc('afterTimeNumber', __, options)])}
           updateAfterTimeType={compose([setOptions, assoc('afterTimeType', __, options)])}