[confighttp] move implementation checks to test files (open-telemetry…

…#9433)

move implementation checks to test files

open-telemetry#9431

config/confighttp/clientinfohandler.go

@@ -11,8 +11,6 @@ import (
 	"go.opentelemetry.io/collector/client"
 )
 
-var _ http.Handler = (*clientInfoHandler)(nil)
-
 // clientInfoHandler is an http.Handler that enhances the incoming request context with client.Info.
 type clientInfoHandler struct {
 	next http.Handler

config/confighttp/clientinfohandler_test.go

@@ -5,11 +5,14 @@ package confighttp // import "go.opentelemetry.io/collector/config/confighttp"
 
 import (
 	"net"
+	"net/http"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
+var _ http.Handler = (*clientInfoHandler)(nil)
+
 func TestParseIP(t *testing.T) {
 	testCases := []struct {
 		desc     string