Chore: Cleanup usageStatsMock duplication (#39710)

* Chore: Cleanup usageStatsMock duplication

* Remove making a new slice for UsageStatsMock

pkg/infra/usagestats/mock.go

@@ -0,0 +1,36 @@
+package usagestats
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+type UsageStatsMock struct {
+	T            testing.TB
+	metricsFuncs []MetricsFunc
+}
+
+func (usm *UsageStatsMock) RegisterMetricsFunc(fn MetricsFunc) {
+	usm.metricsFuncs = append(usm.metricsFuncs, fn)
+}
+
+func (usm *UsageStatsMock) GetUsageReport(_ context.Context) (Report, error) {
+	all := make(map[string]interface{})
+	for _, fn := range usm.metricsFuncs {
+		fnMetrics, err := fn()
+		require.NoError(usm.T, err)
+
+		for name, value := range fnMetrics {
+			all[name] = value
+		}
+	}
+	return Report{Metrics: all}, nil
+}
+
+func (usm *UsageStatsMock) ShouldBeReported(_ string) bool {
+	return true
+}
+
+func (usm *UsageStatsMock) RegisterSendReportCallback(_ SendReportCallbackFunc) {}