Fix eslint rules

[MAILPOET-1348]

assets/js/src/newsletters/send/welcome.jsx

@@ -1,15 +1,8 @@
-define(
-  [
-    'mailpoet',
-    'wp-js-hooks',
-    'newsletters/types/welcome/scheduling.jsx',
-  ],
-  (
-    MailPoet,
-    Hooks,
-    Scheduling
-  ) => {
-    let fields = [
+import MailPoet from 'mailpoet';
+import Hooks from 'wp-js-hooks';
+import Scheduling from 'newsletters/types/welcome/scheduling.jsx';
+
+let fields = [
   {
     name: 'subject',
     label: MailPoet.I18n.t('subjectLine'),
@@ -71,11 +64,11 @@ define(
       },
     ],
   },
-    ];
+];
 
-    fields = Hooks.applyFilters('mailpoet_newsletters_3rd_step_fields', fields);
+fields = Hooks.applyFilters('mailpoet_newsletters_3rd_step_fields', fields);
 
-    return {
+module.export = {
   getFields: function getFields() {
     return fields;
   },
@@ -84,6 +77,4 @@ define(
       value: MailPoet.I18n.t('activate'),
     };
   },
-    };
-  }
-);
+};