I have tested the same at my end on AEM cloud(updated the environment) and it works fine :  27.04.2021 09:59:55.445 [cm-p............d] *DEBUG* [127.0.0.1 [1619517595444] GET /libs/granite/core/content/login.html HTTP/1.1] com.ceamcdublinprogram.core.filters.LoggingFilter request for /libs/granite/c...

Refer to this page  Mobile Core is also configured with the AppID. This is the ID that matches the mobile application with the configuration published in Adobe Platform Launch.HTH.

Make sure we use the 'Publishing Flow' to publish all the resources by adding in the library, in the Launch console. Only then "https://assets.adobedtm.com/file-staging.json"  would be available. Hope that helps. Cheers,Wasil