Feature Request: Add a way to clear down AppConfiguration stores on bicep deploy

When I change my configuration for my app the old keys remain, this means I have to clean up the old keys manually
Which I may not do, because I got distracted by a donut or something, leaving old settings confusing other developers or new members of the team

If a configuration property could be added that would clear down the keys somehow that would be super.

Could this work?

```bicep
resource appConfig 'Microsoft.AppConfiguration/configurationStores@2023-09-01-preview' = {
name: appConfigName
location: location
sku: {
name: 'standard'
}
properties: {
createMode: 'Clean'
}
}
```

although 'createMode' does suggest it only happens when the resource is not found or deleted

would another property work?

```bicep
...
properties: {
clean: true
}
...
```

Thank you

Start with the Microsoft.AppConfiguration/configurationStores@2023-09-01-preview resource example and determine whether createMode or another property can clear removed keys during a Bicep deployment. No repository files or tests are named; done means a supported, unambiguous configuration option is identified and documented or implemented without affecting unrelated deployments.

Written by the indexing model from the issue text.