Fix a ML file inclusion that creates an error

Error: Failed to load chrome://global/content/ml/EngineProcess.sys.mjs
    updateModelMetric moz-src:///browser/components/aiwindow/ui/modules/SmartWindowTelemetry.sys.mjs:91
    init moz-src:///browser/components/aiwindow/ui/modules/SmartWindowTelemetry.sys.mjs:66
    init moz-src:///browser/components/aiwindow/ui/modules/AIWindow.sys.mjs:133
    fn resource://gre/modules/BrowserUtils.sys.mjs:83
    callSingleListener resource://gre/modules/BrowserUtils.sys.mjs:763
    callModulesFromCategory resource://gre/modules/BrowserUtils.sys.mjs:808
    _delayedStartup chrome://browser/content/browser-init.js:554