For anyone else wondering if they will get an explicit response, as far as we know, we also did not receive one. An easier way to see if this has been granted is to go to the Certificates, Identifiers & Profiles section in the developer centre, find your App ID, and if you click into it and this has been granted, you will find a new tab under Edit your App ID Configuration called "Additional Capabilities", which the critical alerts entitlement sits under. We have access to other companies app store accounts as well as the one we requested the entitlement on so I can confirm that this tab does not show unless Apple have granted you this capability!