fix(helm): Use burst limit setting for discovery

When --burst-limit/$HELM_BURST_LIMIT is set, the specified value is not
currently used for the discovery client instantiated by
genericclioptions. This change sets genericclioptions.discoveryBurst to
the value of --burst-limit, meaning it should now be possible to fix
client-side throttling issues encountered by the discovery client.

This value is only configured if --burst-limit is actually set. If
--burst-limit is set to the default value, then discoveryBurst should be
left at its default of 300.

Closes #13128

Signed-off-by: Evan Foster <efoster@adobe.com>
(cherry picked from commit 69362df367)

pkg/cli/environment.go

@@ -112,7 +112,7 @@ func New() *EnvSettings {
 	env.Debug, _ = strconv.ParseBool(os.Getenv("HELM_DEBUG"))
 
 	// bind to kubernetes config flags
-	env.config = &genericclioptions.ConfigFlags{
+	config := &genericclioptions.ConfigFlags{
 		Namespace:        &env.namespace,
 		Context:          &env.KubeContext,
 		BearerToken:      &env.KubeToken,
@@ -133,6 +133,11 @@ func New() *EnvSettings {
 			return config
 		},
 	}
+	if env.BurstLimit != defaultBurstLimit {
+		config = config.WithDiscoveryBurst(env.BurstLimit)
+	}
+	env.config = config
+
 	return env
 }