[Glitch] Convert notifications policies frontend code to Typescript

Port d558dfd77d to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/api/notification_policies.ts

@@ -0,0 +1,10 @@
+import { apiRequest } from 'flavours/glitch/api';
+import type { NotificationPolicyJSON } from 'flavours/glitch/api_types/notification_policies';
+
+export const apiGetNotificationPolicy = () =>
+  apiRequest<NotificationPolicyJSON>('GET', '/v1/notifications/policy');
+
+export const apiUpdateNotificationsPolicy = (
+  policy: Partial<NotificationPolicyJSON>,
+) =>
+  apiRequest<NotificationPolicyJSON>('PUT', '/v1/notifications/policy', policy);