fix(manager/npm): improve handling of grouped updates (#31326)

lib/modules/manager/npm/artifacts.ts

@@ -2,7 +2,7 @@ import upath from 'upath';
 import { logger } from '../../../logger';
 import { exec } from '../../../util/exec';
 import type { ExecOptions } from '../../../util/exec/types';
-import { readLocalFile } from '../../../util/fs';
+import { readLocalFile, writeLocalFile } from '../../../util/fs';
 import { regEx } from '../../../util/regex';
 import type { UpdateArtifact, UpdateArtifactsResult } from '../types';
 import { getNodeToolConstraint } from './post-update/node-version';
@@ -37,6 +37,9 @@ export async function updateArtifacts({
     return null;
   }
 
+  // write old updates before executing corepack update so that they are not removed from package file
+  await writeLocalFile(packageFileName, existingPackageFileContent);
+
   // Asumming that corepack only needs to modify the package.json file in the root folder
   // As it should not be regular practice to have different package managers in different workspaces
   const pkgFileDir = upath.dirname(packageFileName);