[chore] [exporter/elasticsearch] Use t.Setenv in the tests (#30379)

exporter/elasticsearchexporter/traces_exporter_test.go

@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
-	"os"
 	"runtime"
 	"strings"
 	"sync"
@@ -111,18 +110,8 @@ func TestTracesExporter_New(t *testing.T) {
 				env = map[string]string{defaultElasticsearchEnvName: ""}
 			}
 
-			oldEnv := make(map[string]string, len(env))
-			defer func() {
-				for k, v := range oldEnv {
-					os.Setenv(k, v)
-				}
-			}()
-
-			for k := range env {
-				oldEnv[k] = os.Getenv(k)
-			}
 			for k, v := range env {
-				os.Setenv(k, v)
+				t.Setenv(k, v)
 			}
 
 			exporter, err := newTracesExporter(zap.NewNop(), test.config)