Element-Android session doesn't encrypt for a dehydrated device about element-android

[giomfo]

reproduced on E-iOS: element-hq/element-ios#7795

[giomfo]

@uhoreg investigated this issue. He observed the following error in the logs:
2024-05-22T22:51:30*074GMT+00:00Z 97 D/ /Tag: WARN matrix_sdk_crypto::identities::manager: Failed to create a new device user_id="" device_id="" error=VerificationError(Signature(signature::Error { source: Some(Verification equation was not satisfied) }))

"Looking at the Android sources, it looks like when it makes the /keys/query request, if I'm reading it correctly, it parses the response into a KeysQueryResponse, the device_keys get parsed into a DeviceKeysWithUnsigned, which only has set properties. Since dehydrated is not one of the properties, it gets dropped, which means that the signature is no longer valid.

Something in there needs to be changed so that any unknown properties still get passed on, otherwise any device keys that have unknown properties will fail the signature check.

I haven't looked at the iOS code, but if it is also failing, then it may have a similar problem."