az network nic ip-config update command is overwriting existing applicationSecurityGroups

### Describe the bug

When running:
```
az network nic ip-config update --name ipconfig1 --nice-name "NIC-Name" --resource-group rg-name --add "applicationSecurityGroups" "id=/subscription/.../asg-name"
```

The result is that only 1 ASG is now part of the NIC instead of being *added* to the list (overwrite instead of add)

I also tried explicitly adding it to an index but that doesn't exist:
```
az network nic ip-config update --name ipconfig1 --nice-name "NIC-Name" --resource-group rg-name --add "applicationSecurityGroups[0]" "id=/subscription/.../asg-name"
```

### Related command

az network nic ip-config update --name ipconfig1 --nice-name "NIC-Name" --resource-group rg-name --add "applicationSecurityGroups" "id=/subscription/.../asg-name"

### Errors

index 0 doesn't exist on applicationSecurityGroups

### Issue script & Debug output

Redacted for sensitivity, can be provided later if required

### Expected behavior

Should not delete existing ASGs

### Environment Summary

az --version
azure-cli 2.54.0

core 2.54.0
telemetry 1.1.0

Extensions:
datafactory 0.10.0

Dependencies:
msal 1.24.0b2
azure-mgmt-resource 23.1.0b2

Python location '/opt/homebrew/Cellar/azure-cli/2.54.0/libexec/bin/python'
Extensions directory '/Users/user/.azure/cliextensions'

Python (Darwin) 3.11.6 (main, Oct 2 2023, 13:45:54) [Clang 15.0.0 (clang-1500.0.40.1)]

Legal docs and information: aka.ms/AzureCliLegal

Your CLI is up-to-date.

### Additional context

_No response_