fix empty string of actionErrorMessage

src/koishi-exception-handler/koishi-exception-handler.service.ts

@@ -22,8 +22,11 @@ export class KoishiExceptionHandlerService extends ConsoleLogger {
       return e.message;
     } else {
       this.error(e.message, e.stack);
+      if (this.koishiModuleOptions.actionErrorMessage === '') {
+        return;
+      }
       return (
-        this.koishiModuleOptions.actionErrorMessage || 'Internal Server Error'
+        this.koishiModuleOptions.actionErrorMessage ?? 'Internal Server Error'
       );
     }
   }

src/providers/koishi-metascan.service.ts

@@ -18,7 +18,6 @@ import { Module } from '@nestjs/core/injector/module';
 import { KoishiMetadataFetcherService } from '../koishi-metadata-fetcher/koishi-metadata-fetcher.service';
 import { KoishiInterceptorManagerService } from '../koishi-interceptor-manager/koishi-interceptor-manager.service';
 import { CommandRegisterConfig, Registrar } from 'koishi-decorators';
-import { handleActionException } from '../utility/wrap-action';
 import { KoishiExceptionHandlerService } from '../koishi-exception-handler/koishi-exception-handler.service';
 
 @Injectable()