Fix deprecation warning

Error reported in CI https://github.com/helm/helm/actions/runs/17623700524/job/50075176523?pr=31231

```
Error: cmd/helm/root.go:165:2: SA1019: flags.ParseErrorsWhitelist is deprecated: use [FlagSet.ParseErrorsAllowlist] instead. This field will be removed in a future release. (staticcheck)
```

Close: #31231
Signed-off-by: Benoit Tigeot <benoit.tigeot@lifen.fr>
(cherry picked from commit 9a366b4474)

cmd/helm/root.go

@@ -162,7 +162,7 @@ func newRootCmd(actionConfig *action.Configuration, out io.Writer, args []string
 	// those errors will be caught later during the call to cmd.Execution.
 	// This call is required to gather configuration information prior to
 	// execution.
-	flags.ParseErrorsWhitelist.UnknownFlags = true
+	flags.ParseErrorsAllowlist.UnknownFlags = true
 	flags.Parse(args)
 
 	registryClient, err := newDefaultRegistryClient(false, "", "")