Can't add new API permissions to an existing server in FlowAuth

[jc-harrison]

Describe the bug
If I log into FlowAuth as an admin user, and add a new API route, the new API permissions appear greyed-out in the 'Edit Server' view for an existing server, and can't be selected.

To Reproduce

1. Spin up FlowAuth in demo mode, and log in as 'TEST_ADMIN'.
2. In the 'API Routes' tab, add a new capability 'available_dates'.
3. Select the 'Servers' tab, and edit 'TEST_SERVER'.
4. Expand the 'API Permissions' block.
5. The 'available_dates' heading is visible, but the tick-boxes are greyed-out.

Expected behavior
When a new API route is added through the FlowAuth UI, it should then be possible to add this as an API permission for an existing server.