refactor: Extract Invitation routes to InvitationController (no-changelog) (#7726)

This PR:

- Creates `InvitationController`
- Moves `POST /users` to `POST /invitations` and move related test to
`invitations.api.tests`
- Moves `POST /users/:id` to `POST /invitations/:id/accept` and move
related test to `invitations.api.tests`
- Adjusts FE to use new endpoints
- Moves all the invitation logic to the `UserService`

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/editor-ui/src/utils/apiUtils.ts

@@ -98,11 +98,11 @@ async function request(config: {
 	}
 }
 
-export async function makeRestApiRequest(
+export async function makeRestApiRequest<T>(
 	context: IRestApiContext,
 	method: Method,
 	endpoint: string,
-	data?: IDataObject,
+	data?: any,
 ) {
 	const response = await request({
 		method,
@@ -113,7 +113,7 @@ export async function makeRestApiRequest(
 	});
 
 	// @ts-ignore all cli rest api endpoints return data wrapped in `data` key
-	return response.data;
+	return response.data as T;
 }
 
 export async function get(