Crosspost doesn’t allow to search community by instance

**Describe the bug**
When I try to search a community by instance on crossposts, no results come up.

**To Reproduce**
Steps to reproduce the behavior:

1. Tap on crosspost
2. Search for community to crosspost
3. Add an "@" to search by instance
4. No results come up

**Expected behavior**
The community of the instance should come up

**Screenshots**


**Smartphone (please complete the following information):**

- Device: iPhone 11 Pro Max
- OS: iOS 18.6.1