az webapp config connection-string set with json file does not remove, just add or update

### Describe the bug

related to https://github.com/Azure/azure-cli/issues/15395

while you can add or update connection string with the bulk pattern, removing doesnt seem to work or is not implemented

### Related command

az webapp config connection-string set --resource-group --name --settings "@connection-string.json"

### Errors

no error

### Issue script & Debug output

no output

### Expected behavior

if a connection string is removed from the json, it should be removed from the app services too

### Environment Summary

azure-cli 2.67.0

core 2.67.0
telemetry 1.1.0

Extensions:
account 0.2.3

Dependencies:
msal 1.31.0
azure-mgmt-resource 23.1.1

### Additional context

_No response_