Fix periodicity strings

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

@@ -23,7 +23,7 @@ define(
       },
       {
         name: 'options',
-        label: MailPoet.I18n.t('selectPeriodicity'),
+        label: MailPoet.I18n.t('selectFrequency'),
         type: 'reactComponent',
         component: Scheduling,
       },

assets/js/src/newsletters/types/notification/notification.jsx

@@ -71,7 +71,7 @@ define(
             <h1>{MailPoet.I18n.t('postNotificationNewsletterTypeTitle')}</h1>
             <Breadcrumb step="type" />
 
-            <h3>{MailPoet.I18n.t('selectPeriodicity')}</h3>
+            <h3>{MailPoet.I18n.t('selectFrequency')}</h3>
 
             <Scheduling
               item={this.state}

views/newsletters.html

@@ -109,8 +109,7 @@
     'setUp': __('Set up'),
     'postNotificationNewsletterTypeTitle': __('Post notifications'),
     'postNotificationsNewsletterTypeDescription': __('Automatically send posts immediately, daily, weekly or monthly. Filter by categories, if you like.'),
-    'selectPeriodicity': __('Select a frequency'),
-    'periodicity': __('Frequency'),
+    'selectFrequency': __('Select a frequency'),
     'postNotificationSubjectLineTip': __("Insert [newsletter:total] to show number of posts, [newsletter:post_title] to show the latest post's title & [newsletter:number] to display the issue number."),
     'activate': __('Activate'),
     'sendWelcomeEmailWhen': __('Send welcome email when...'),