AIFeature.sys.mjs failures in 149 desktop builds

@pierov mentioned some errors in AIFeature.sys.mjs when running 149 desktop builds:

!1913 (comment 3370706)

Error: Failed to load chrome://global/content/ml/AIFeature.sys.mjs
    get AIFeature resource://gre/actors/TranslationsParent.sys.mjs:467
    _updateElementsForContentType chrome://browser/content/browser.js:2417

Error: Failed to load chrome://global/content/ml/AIFeature.sys.mjs
    get AIFeature resource://gre/actors/TranslationsParent.sys.mjs:467
    onLocationChange chrome://browser/content/translations/fullPageTranslationsPanel.js:1430

Uncaught Error: Failed to load chrome://global/content/ml/AIFeature.sys.mjs
    get AIFeature resource://gre/actors/TranslationsParent.sys.mjs:467
    onLoad chrome://browser/content/browser-init.js:268

/cc @henry