Refactor server reducer into TypeScript (#39089)

app/javascript/mastodon/models/server.ts

@@ -0,0 +1,21 @@
+import type {
+  ApiInstanceJSON,
+  ApiExtendedDescriptionJSON,
+  ApiDomainBlockJSON,
+} from 'mastodon/api_types/instance';
+
+export type Server = ApiInstanceJSON;
+
+export const createServerFromServerJSON = (obj: ApiInstanceJSON): Server => obj;
+
+export type ExtendedDescription = ApiExtendedDescriptionJSON;
+
+export const createExtendedDescriptionFromServerJSON = (
+  obj: ApiExtendedDescriptionJSON,
+): ExtendedDescription => obj;
+
+export type DomainBlock = ApiDomainBlockJSON;
+
+export const createDomainBlockFromServerJSON = (
+  obj: ApiDomainBlockJSON,
+): DomainBlock => obj;