migrating an asset field with extension validation gives an error on upload

[verybigelephants]

i am migrating a fieldset with this asset field:

      hero_image_video:
        container: main
        folder: entries/images-videos
        restrict: false
        mode: grid
        type: assets
        localizable: true
        display: 'Hero image/video'
        validate: 'ext:jpg,jpeg,gif,png,svg,mp4'
        max_files: 1

after migrating it and trying to saving something after an upload i am getting this message:

 "message": "Method Illuminate\\Validation\\Validator::validateExt does not exist.",
    "exception": "BadMethodCallException",
    "file": "C:\\programs\\laragon\\www\\queermemory2\\vendor\\laravel\\framework\\src\\Illuminate\\Validation\\Validator.php",
    "line": 1382,