Remove obsolete link.xml

Assets/link.xml

-<linker>
-    <assembly fullname="Unity.XR.ARCore" ignoreIfMissing="1" preserve="none"/>
-    <assembly fullname="Unity.XR.ARKit" ignoreIfMissing="1" preserve="none"/>
-    <assembly fullname="Unity.XR.ARKit.FaceTracking" ignoreIfMissing="1" preserve="none"/>
-</linker>

Assets/link.xml.meta

-fileFormatVersion: 2
-guid: ee957744b1fd90c429ee647899f73f60
-TextScriptImporter:
-  externalObjects: {}
-  userData: 
-  assetBundleName: 
-  assetBundleVariant: