Validate the file listsize based on the total size of the files in the list.

The ListSizeValidator extension can be configured with the ListSizeValidatorOptions object. 

import { defineFilePond } from 'filepond';
import { locale } from 'filepond/locales/en-gb.js';
import { ListSizeValidator } from 'filepond/extensions/list-size-validator.js';

defineFilePond({
    locale,
    extensions: [
        // Add the ListSizeValidator extension and configure with ListSizeValidatorOptions object
        [ListSizeValidator, {
            maxListSize: '50MB'
        }]
    ]
})