Try to appease golangci-lint with import groups

Author: odeke-em

receiver/prometheusreceiver/internal/otlp_metricsbuilder_test.go

@@ -23,9 +23,9 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
-	"go.opentelemetry.io/collector/consumer/pdata"
-
 	metricspb "github.com/census-instrumentation/opencensus-proto/gen-go/metrics/v1"
+
+	"go.opentelemetry.io/collector/consumer/pdata"
 )
 
 func TestGetBoundaryEquivalence(t *testing.T) {