Unable to add or remove client from default read/write in language resources

Problem

Adding or removing client from default read/write in the language resources is not possible.

In addition to that, default clients are not rendered in the language resources column anymore.

To reproduce

1. Open resource for editing where client is already added as default read/write
2. Remove the client and save the resource
3. Open the resource again, the client is still selected
4. Same steps above for adding new default client