Remove search delay in events admin screen

Previous behaviour

When searching for members in the EventAdminScreen, there is a delay of 500 milliseconds before the search request is handled. However, this is unnecessary in this screen, since all data is already loaded in the app. Therefore, there is no risk of sending an unnecessary amount of requests.

Steps to reproduce:

1. Open the events admin screen
2. Search for a member
3. Notice a small delay

New behaviour

There is no delay.

Steps to validate that it works:

1. Open the events admin screen
2. Search for a member
3. Notice there is no delay