fix: ListScopes must not return null (#5356)

The ListScopes endpoint was responsing with a "null" body instead of "[]" when there was no scope.

Co-authored-by: Camille Teruel <camille.teruel@meri.co>
diff --git a/backend/plugins/github/models/migrationscripts/register.go b/backend/plugins/github/models/migrationscripts/register.go
index 518f347..676471c 100644
--- a/backend/plugins/github/models/migrationscripts/register.go
+++ b/backend/plugins/github/models/migrationscripts/register.go
@@ -23,7 +23,6 @@
 
 // All return all the migration scripts
 func All() []plugin.MigrationScript {
-	println("github register.go")
 	return []plugin.MigrationScript{
 		new(addInitTables),
 		new(addGithubRunsTable),
diff --git a/backend/python/test/fakeplugin/fakeplugin/main.py b/backend/python/test/fakeplugin/fakeplugin/main.py
index 55c5489..213641b 100644
--- a/backend/python/test/fakeplugin/fakeplugin/main.py
+++ b/backend/python/test/fakeplugin/fakeplugin/main.py
@@ -18,10 +18,9 @@
 from typing import Optional
 import json
 
-from sqlmodel import Field
 from pydantic import SecretStr
 
-from pydevlake import Plugin, Connection, TransformationRule, Stream, ToolModel, ToolScope, RemoteScopeGroup, DomainType
+from pydevlake import Plugin, Connection, TransformationRule, Stream, ToolModel, ToolScope, RemoteScopeGroup, DomainType, Field
 from pydevlake.domain_layer.devops import CicdScope, CICDPipeline, CICDStatus, CICDResult, CICDType
 
 VALID_TOKEN = "this_is_a_valid_token"
diff --git a/backend/server/services/remote/plugin/scope_api.go b/backend/server/services/remote/plugin/scope_api.go
index 0d1839f..bc768fa 100644
--- a/backend/server/services/remote/plugin/scope_api.go
+++ b/backend/server/services/remote/plugin/scope_api.go
@@ -18,9 +18,10 @@
 package plugin
 
 import (
+	"net/http"
+
 	"github.com/apache/incubator-devlake/server/services/remote/models"
 	"github.com/mitchellh/mapstructure"
-	"net/http"
 
 	"github.com/apache/incubator-devlake/core/errors"
 	"github.com/apache/incubator-devlake/core/plugin"
@@ -103,8 +104,8 @@
 
 // convertScopeResponse adapt the "remote" scopes to a serializable api.ScopeRes
 func convertScopeResponse(scopes ...*api.ScopeRes[models.RemoteScope]) ([]map[string]any, errors.Error) {
-	var responses []map[string]any
-	for _, scope := range scopes {
+	responses := make([]map[string]any, len(scopes))
+	for i, scope := range scopes {
 		resMap := map[string]any{}
 		err := models.MapTo(api.ScopeRes[map[string]any]{
 			Scope:                  nil, //ignore intentionally
@@ -123,7 +124,7 @@
 		for k, v := range scopeMap {
 			resMap[k] = v
 		}
-		responses = append(responses, resMap)
+		responses[i] = resMap
 	}
 	return responses, nil
 }