Field upload throw error when filter reject the file.

I am uploading two image using `.fields([{ name: 'certificateImage', maxCount: 1 }, { name: 'addressProofImage', maxCount: 1 }]); ` but it is throwing error when filefilter reject the file

error
```
if (this.req.files[placeholder.fieldname].length === 1) {
^

TypeError: Cannot read properties of undefined (reading 'length')
```

Multer throw error at line 49 in file-appender.js. req.files[placeholder.fieldname] is showing undefined.
```
case 'OBJECT':
if (this.req.files[placeholder.fieldname].length === 1) {
delete this.req.files[placeholder.fieldname]
} else {
arrayRemove(this.req.files[placeholder.fieldname], placeholder)
}
break

```

My code

```
const multer = require('multer');
const path = require('path');

var storage = multer.diskStorage({
destination: function (req, file, cb) {
console.log('type',req.body.type);
cb(null, "uploads/images/");
},
filename: function (req, file, cb) {
cb(
null,
file.fieldname + "-" + Date.now() + path.extname(file.originalname)
);
},
});

const maxSize = 1 * 1024 * 1024; // for 1MB

var upload = multer({
storage: storage,
fileFilter: async (req, file, cb) => {

var ext = path.extname(file.originalname);
console.log("ext", ext);

let validImageExtensions = ['png', 'jpg', 'jpeg'];

if (validImageExtensions.indexOf(ext.substring(1)) === -1) {
cb(null, false);
console.log("invalid extension");
return cb(new Error("Only " + validImageExtensions + " are allowed with maxsize 1MB"));
}else{
console.log("valid extension");
cb(null, true);
}
},
limits: { fileSize: maxSize },
});

module.exports = upload;
```

everything work fine if file extension match and image store in upload folder but throw same error when extension doesnt not match.

I have created github repo for the you to better to test error.
[https://github.com/AlexAdvent/multer-multiple-issue](https://github.com/AlexAdvent/multer-multiple-issue)

and send put request at url localhost:8000/upload-image after running serve.