fix(azure): Consumption legacy usage details (#11242)

Fixes cloudquery/cloudquery-issues#565

This fix ignores all returned types except `LegacyUsageDetail` from the API call (which can sometimes include `ModernUsageDetail` for some undocumented reason, to our understanding) but since we have another resource listing those (`azure_consumption_billing_account_modern_usage_details`) we don't want them here.

```go
// UsageDetailClassification provides polymorphic access to related types.
// Call the interface's GetUsageDetail() method to access the common type.
// Use a type switch to determine the concrete type.  The possible types are:
// - *LegacyUsageDetail, *ModernUsageDetail, *UsageDetail
type UsageDetailClassification interface {
	// GetUsageDetail returns the UsageDetail content of the underlying type.
	GetUsageDetail() *UsageDetail
}
```

plugins/source/azure/resources/services/consumption/subscription_legacy_usage_details.go

@@ -32,7 +32,11 @@ func fetchSubscriptionLegacyUsageDetails(ctx context.Context, meta schema.Client
 			return err
 		}
 		for _, v := range p.Value {
-			res <- v.(*armconsumption.LegacyUsageDetail)
+			lud, ok := v.(*armconsumption.LegacyUsageDetail)
+			if !ok {
+				continue // skip
+			}
+			res <- lud
 		}
 	}
 	return nil

plugins/source/azure/resources/services/consumption/subscription_legacy_usage_details_test.go

@@ -3,7 +3,6 @@ package consumption
 import (
 	"encoding/json"
 	"net/http"
-
 	"testing"
 
 	"github.com/Azure/azure-sdk-for-go/sdk/azcore/to"
@@ -14,16 +13,24 @@ import (
 )
 
 func createSubscriptionLegacyUsageDetails(router *mux.Router) error {
-	var item armconsumption.LegacyUsageDetail
-	if err := faker.FakeObject(&item); err != nil {
+	var (
+		item1 armconsumption.LegacyUsageDetail
+		item2 armconsumption.ModernUsageDetail
+	)
+	if err := faker.FakeObject(&item1); err != nil {
+		return err
+	}
+	item1.Kind = to.Ptr(armconsumption.UsageDetailsKindLegacy)
+
+	if err := faker.FakeObject(&item2); err != nil {
 		return err
 	}
-	item.Kind = to.Ptr(armconsumption.UsageDetailsKindLegacy)
+	item2.Kind = to.Ptr(armconsumption.UsageDetailsKindModern) // will be skipped, but API seems to return both
 
 	resp := armconsumption.UsageDetailsClientListResponse{
 		UsageDetailsListResult: armconsumption.UsageDetailsListResult{
 			// Value is an interface{} so we can't mock it directly
-			Value: []armconsumption.UsageDetailClassification{&item},
+			Value: []armconsumption.UsageDetailClassification{&item1, &item2},
 		},
 	}
 	resp.NextLink = to.Ptr("")