bug: ignore diagnostics settings categories that are not enabled

When setting diagnostic settings, any that are not enabled should be removed from the items returned.

e.g. for a storage account, if you set "StorageDelete" and "StorageWrite", on subsequent plans you will see this:

```
~ resource "azapi_resource" "diagnostic_settings" {
~ body = {
~ properties = {
~ logs = [
{
category = "StorageDelete"
categoryGroup = null
enabled = true
},
- {
- category = "StorageRead"
- categoryGroup = null
- enabled = false
},
{
category = "StorageWrite"
categoryGroup = null
enabled = true
},
]
# (7 unchanged attributes hidden)
```

No file or test is named. Reproduce the storage-account diagnostic-settings plan described in the issue, then trace how diagnostic settings are returned and compare the resulting logs with the enabled categories; done means disabled categories are omitted and subsequent plans show no spurious diff.

Written by the indexing model from the issue text.