Allow MacOS Users who had an airtag shared with them to export those AirTags

[parawanderer]

This comes down to this issue: malmeloo/FindMy.py#34

ATM the Apple User who is the at the time logged-in user of the iOS device that was used to register the AirTags has to be the user logged in to the MacOS computer that is used to export the tag data (until above issue is figured out). Basically, you kind of need to plan around who should be the "owner account" at the moment.

The exporter app will not even show those "Shared" tags as available for export.

[parawanderer]

So from my side I already looked into this a bit and the problem is that shared AirTags go to a separate file in "SharedBeacons" (vs owned tags going to "OwnedBeacons") which contains less keys and is missing the privateKey that the FindMy.py library expects.

So we can't just include "SharedBeacons" in the app before figuring out how we can go from the keys that are in the "SharedBeacons" file to some key that can actually be used to query the Apple servers.

I personally think that the commenter in the thread above is right that Apple designed this Sharing system to make it so that un-sharing a device would throw you out of being able to access it, so the Shared token that is available in that file is probably being converted to a query token via some API.

But to investigate that you need to bypass SSL/TLS of the FindMy app and investigate the network traffic using wireshark or something.

Until then the UI sadly has to pretend those Tags aren't even available (current behaviour)