[chore] address linting issues in generated tests (#30452)

This addresses the following lint failure:

```
var-naming: don't use underscores in Go names; func Test_ComponentLifecycle should be TestComponentLifecycle (revive)
func Test_ComponentLifecycle(t *testing.T) {
```

Signed-off-by: Alex Boten <[email protected]>

Author: Alex Boten

cmd/mdatagen/lint_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func Test_formatIdentifier(t *testing.T) {
+func TestFormatIdentifier(t *testing.T) {
 	var tests = []struct {
 		input    string
 		want     string

cmd/mdatagen/loader_test.go

@@ -11,7 +11,7 @@ import (
 	"go.opentelemetry.io/collector/pdata/pmetric"
 )
 
-func Test_loadMetadata(t *testing.T) {
+func TestLoadMetadata(t *testing.T) {
 	tests := []struct {
 		name    string
 		want    metadata

cmd/mdatagen/main_test.go

@@ -16,7 +16,7 @@ import (
 	md "github.com/open-telemetry/opentelemetry-collector-contrib/cmd/mdatagen/internal/metadata"
 )
 
-func Test_runContents(t *testing.T) {
+func TestRunContents(t *testing.T) {
 	tests := []struct {
 		yml                  string
 		wantMetricsGenerated bool
@@ -96,7 +96,7 @@ foo
 	}
 }
 
-func Test_run(t *testing.T) {
+func TestRun(t *testing.T) {
 	type args struct {
 		ymlPath string
 	}
@@ -125,7 +125,7 @@ func Test_run(t *testing.T) {
 	}
 }
 
-func Test_inlineReplace(t *testing.T) {
+func TestInlineReplace(t *testing.T) {
 	tests := []struct {
 		name           string
 		markdown       string

cmd/mdatagen/templates/component_test.go.tmpl

@@ -55,7 +55,7 @@ func (aneh *assertNoErrorHost) ReportFatalError(err error) {
 
 
 {{ if isExporter }}
-func Test_ComponentLifecycle(t *testing.T) {
+func TestComponentLifecycle(t *testing.T) {
 	factory := NewFactory()
 
 	tests := []struct{
@@ -146,7 +146,7 @@ func Test_ComponentLifecycle(t *testing.T) {
 {{ end }}
 
 {{ if isProcessor }}
-func Test_ComponentLifecycle(t *testing.T) {
+func TestComponentLifecycle(t *testing.T) {
 	factory := NewFactory()
 
 	tests := []struct{
@@ -235,7 +235,7 @@ func Test_ComponentLifecycle(t *testing.T) {
 {{ end }}
 
 {{ if isReceiver }}
-func Test_ComponentLifecycle(t *testing.T) {
+func TestComponentLifecycle(t *testing.T) {
 	factory := NewFactory()
 
 	tests := []struct{
@@ -304,7 +304,7 @@ func Test_ComponentLifecycle(t *testing.T) {
 {{ end }}
 
 {{ if isExtension }}
-func Test_ComponentLifecycle(t *testing.T) {
+func TestComponentLifecycle(t *testing.T) {
 	factory := NewFactory()
 
 	cm, err := confmaptest.LoadConf("metadata.yaml")