feat: provide appId to webpack config (#5778)

Author: farfromrefug

lib/services/webpack/webpack-compiler-service.ts

@@ -361,11 +361,13 @@ export class WebpackCompilerService
 		const { env } = prepareData;
 		const envData = Object.assign({}, env, { [platform.toLowerCase()]: true });
 
+		const appId = projectData.projectIdentifiers[platform];
 		const appPath = projectData.getAppDirectoryRelativePath();
 		const appResourcesPath = projectData.getAppResourcesRelativeDirectoryPath();
 
 		Object.assign(
 			envData,
+			appId && { appId },
 			appPath && { appPath },
 			appResourcesPath && { appResourcesPath },
 			{