Cannot create a Subscriber in a Network Slice with more than one Device Group

[patriciareinoso]

Describe the bug

Cannot create a Subscriber in a Network Slice with more than one Device Group

To Reproduce

1. Create a Network Slice A
2. A default Device Group is created due to https://github.com/canonical/sdcore-nms/pull/200
3. Add a second Device Group in Network Slice A
4. Try to create a subscriber over the Network Slice A -> Both Device Groups will be shown on the list but is not possible to select either of them.

Expected behavior

We can create a Subscriber in a Network Slice that has more than one Device Group.

Environment

• Node version: v20.9.0

[patriciareinoso]

In the future we will be able to associate one subscriber to one or more device group ?