Use Immutable Record for accounts in Redux state (#26559)

app/javascript/mastodon/actions/account_notes.ts

@@ -1,3 +1,4 @@
+import type { ApiRelationshipJSON } from 'mastodon/api_types/relationships';
 import { createAppAsyncThunk } from 'mastodon/store/typed_functions';
 
 import api from '../api';
@@ -5,8 +6,7 @@ import api from '../api';
 export const submitAccountNote = createAppAsyncThunk(
   'account_note/submit',
   async (args: { id: string; value: string }, { getState }) => {
-    // TODO: replace `unknown` with `ApiRelationshipJSON` when it is merged
-    const response = await api(getState).post<unknown>(
+    const response = await api(getState).post<ApiRelationshipJSON>(
       `/api/v1/accounts/${args.id}/note`,
       {
         comment: args.value,