[chore] [exporter/mezmo] Use NewDefaultClientConfig instead of manual…

…ly creating struct

**Description:**
This PR makes usage of `NewDefaultClientConfig` instead of manually creating the confighttp.ClientConfig struct.

**Link to tracking Issue:** open-telemetry#35457

exporter/mezmoexporter/config.go

@@ -46,9 +46,9 @@ type Config struct {
 
 // returns default http client settings
 func createDefaultClientConfig() confighttp.ClientConfig {
-	return confighttp.ClientConfig{
-		Timeout: defaultTimeout,
-	}
+	clientConfig := confighttp.NewDefaultClientConfig()
+	clientConfig.Timeout = defaultTimeout
+	return clientConfig
 }
 
 func (c *Config) Validate() error {

exporter/mezmoexporter/factory_test.go

@@ -5,12 +5,14 @@ package mezmoexporter
 
 import (
 	"context"
+	"net/http"
 	"testing"
 	"time"
 
 	"github.com/stretchr/testify/assert"
 	"go.opentelemetry.io/collector/component/componenttest"
 	"go.opentelemetry.io/collector/config/confighttp"
+	"go.opentelemetry.io/collector/config/configopaque"
 	"go.opentelemetry.io/collector/config/configretry"
 	"go.opentelemetry.io/collector/exporter/exporterhelper"
 	"go.opentelemetry.io/collector/exporter/exportertest"
@@ -25,6 +27,11 @@ func TestType(t *testing.T) {
 }
 
 func TestCreateDefaultConfig(t *testing.T) {
+	defaultMaxIdleConns := http.DefaultTransport.(*http.Transport).MaxIdleConns
+	defaultMaxIdleConnsPerHost := http.DefaultTransport.(*http.Transport).MaxIdleConnsPerHost
+	defaultMaxConnsPerHost := http.DefaultTransport.(*http.Transport).MaxConnsPerHost
+	defaultIdleConnTimeout := http.DefaultTransport.(*http.Transport).IdleConnTimeout
+
 	factory := NewFactory()
 	cfg := factory.CreateDefaultConfig()
 
@@ -33,7 +40,12 @@ func TestCreateDefaultConfig(t *testing.T) {
 		IngestKey: "",
 
 		ClientConfig: confighttp.ClientConfig{
-			Timeout: 5 * time.Second,
+			Timeout:             5 * time.Second,
+			MaxIdleConns:        &defaultMaxIdleConns,
+			MaxIdleConnsPerHost: &defaultMaxIdleConnsPerHost,
+			MaxConnsPerHost:     &defaultMaxConnsPerHost,
+			IdleConnTimeout:     &defaultIdleConnTimeout,
+			Headers:             map[string]configopaque.String{},
 		},
 		BackOffConfig: configretry.NewDefaultBackOffConfig(),
 		QueueSettings: exporterhelper.NewDefaultQueueConfig(),