Instance/device limit can be set lower than the number of included instances

### Current Behavior

Admins are able to set an instance/device limit that is lower than the number of included (free) instances provided by the team tier. This results in an inconsistent state where the limit blocks usage that should be allowed.

### Expected Behavior

The instance/device limit should never be allowed to be set below the number of included (free) instances for the team tier.

### Steps To Reproduce

1. Navigate to admin team type settings or manual team quota configuration
2. Attempt to set the instance/device limit below the number of included instances
3. Observe that the change is accepted despite being lower than the included quota

### Environment

- FlowFuse version: 2.20.0
- Node.js version: N/A
- npm version: N/A
- Platform/OS: N/A
- Browser: N/A

### Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate