When adding a filter to a Repeater Block, when I switch to Custom datasource, the filter incorrectly remains

**Describe the bug**
1. Add a SQL repeater block with a filter
2. Change the data source to 'Custom'
3. See that the filter remains, but I can't remove it

**Screenshots**
<img width="1122" height="448" alt="Image" src="https://github.com/user-attachments/assets/33ce0370-9296-404e-a450-2389b54d0311" />

