Fix width of select for WC subscription

[MAILPOET-3469]

assets/js/src/segments/dynamic/dynamic_segments_filters/woocommerce_subscription.tsx

@@ -57,6 +57,7 @@ export const WooCommerceSubscriptionFields: React.FunctionComponent<Props> = ({
     <div>
       <Select
         dimension="small"
+        isFullWidth
         placeholder={MailPoet.I18n.t('selectWooSubscription')}
         automationId="segment-woo-subscription-action"
         options={productOptions}