优化代码逻辑，修复潜在播放问题

src/main/modules/userApi/main.ts

@@ -27,7 +27,7 @@ const winEvent = () => {
 
 export const createWindow = async(userApi: LX.UserApi.UserApiInfo) => {
   await closeWindow()
-  if (!dir) dir = global.isDev ? webpackUserApiPath : join(encodePath(__dirname), 'userApi')
+  dir ??= global.isDev ? webpackUserApiPath : join(encodePath(__dirname), 'userApi')
 
   if (!html) {
     html = await fs.promises.readFile(join(dir, 'renderer/user-api.html'), 'utf8')

src/main/modules/userApi/utils.ts

@@ -33,7 +33,7 @@ export const importApi = (script: string): LX.UserApi.UserApiInfo => {
     script,
     allowShowUpdateAlert: true,
   }
-  if (!userApis) userApis = []
+  userApis ??= []
   userApis.push(apiInfo)
   getStore(STORE_NAMES.USER_API).set('userApis', userApis)
   return apiInfo