heal: Return parity for storage classes in heal info API (#13038)

`mc admin heal` command will show servers/disks tolerance, for that
purpose, you need to know the number of parity disks for each storage
class.

Parity is always the same in all pools.

cmd/global-heal.go

@@ -26,6 +26,7 @@ import (
 
 	"github.com/minio/madmin-go"
 	"github.com/minio/minio/internal/color"
+	"github.com/minio/minio/internal/config/storageclass"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/console"
 	"github.com/minio/pkg/wildcard"
@@ -133,6 +134,11 @@ func getBackgroundHealStatus(ctx context.Context, o ObjectLayer) (madmin.BgHealS
 		return status.Sets[i].ID < status.Sets[j].ID
 	})
 
+	backendInfo := o.BackendInfo()
+	status.SCParity = make(map[string]int)
+	status.SCParity[storageclass.STANDARD] = backendInfo.StandardSCParity
+	status.SCParity[storageclass.RRS] = backendInfo.RRSCParity
+
 	return status, true
 
 }