Crypto: Threading: Do things on right thread (8/X)
Crypto: Threading: Do things on right thread (8/X)

Refactor [MXCrypto setDeviceVerification] so that MXSession access is done on the main thread.

matrix-org/matrix-ios-sdk,matrix-org/matrix-ios-sdk,matrix-org/matrix-ios-sdk,matrix-org/matrix-ios-sdk,matrix-org/matrix-ios-sdk