refactor: replace experimental maps and slices with stdlib (#20679)

The experimental functions are now available in the standard library in
Go 1.23 [1].

[1]: https://go.dev/doc/go1.23#new-unique-package

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

cmd/metrics-v3-types.go

@@ -20,6 +20,7 @@ package cmd
 import (
 	"context"
 	"fmt"
+	"slices"
 	"strings"
 	"sync"
 
@@ -27,7 +28,6 @@ import (
 	"github.com/minio/minio/internal/logger"
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
-	"golang.org/x/exp/slices"
 )
 
 type collectorPath string