Fix numeric select values not being passed as strings

[MAILPOET-4323]

mailpoet/assets/js/src/form_editor/components/form_settings/form_placement_options/settings_panels/cookie_settings.tsx

@@ -21,15 +21,15 @@ export function CookieSettings({ settingsPlacementKey }: Props): JSX.Element {
       value={formSettings.formPlacement[settingsPlacementKey].cookieExpiration}
       options={[
         {
-          value: 0,
+          value: '0',
           label: MailPoet.I18n.t('formPlacementCookieExpirationAlways'),
         },
         {
-          value: 1,
+          value: '1',
           label: MailPoet.I18n.t('formPlacementCookieExpirationDay'),
         },
         ...cookieExpirationValues.map((cookieExpirationValue) => ({
-          value: cookieExpirationValue,
+          value: `${cookieExpirationValue}`,
           label: MailPoet.I18n.t('formPlacementCookieExpirationDays').replace(
             '%1s',
             cookieExpirationValue.toString(),

mailpoet/assets/js/src/form_editor/components/form_settings/form_placement_options/settings_panels/fixed_bar_settings.tsx

@@ -83,7 +83,7 @@ export function FixedBarSettings(): JSX.Element {
               assocPath('formPlacement.fixedBar.delay', __, formSettings),
             ])}
             options={delayValues.map((delayValue) => ({
-              value: delayValue,
+              value: `${delayValue}`,
               label: MailPoet.I18n.t('formPlacementDelaySeconds').replace(
                 '%1s',
                 `${delayValue}`,

mailpoet/assets/js/src/form_editor/components/form_settings/form_placement_options/settings_panels/popup_settings.tsx

@@ -62,7 +62,7 @@ export function PopUpSettings(): JSX.Element {
               assocPath('formPlacement.popup.delay', __, formSettings),
             ])}
             options={delayValues.map((delayValue) => ({
-              value: delayValue,
+              value: `${delayValue}`,
               label: MailPoet.I18n.t('formPlacementDelaySeconds').replace(
                 '%1s',
                 `${delayValue}`,

mailpoet/assets/js/src/form_editor/components/form_settings/form_placement_options/settings_panels/slide_in_settings.tsx

@@ -83,7 +83,7 @@ export function SlideInSettings(): JSX.Element {
               assocPath('formPlacement.slideIn.delay', __, formSettings),
             ])}
             options={delayValues.map((delayValue) => ({
-              value: delayValue,
+              value: `${delayValue}`,
               label: MailPoet.I18n.t('formPlacementDelaySeconds').replace(
                 '%1s',
                 `${delayValue}`,