Take big endian inputs in ExCryptBnQwBeSigDifference

[InvoxiPlayGames]

Previously, when providing an XECRYPT_RSA2048_PUB byte formatted structure (taken from a running console byte-for-byte), ExCryptBnQwBeSigVerify returned false. This swaps the input endianness of the public key into big endian (cloned into the stack, not affecting the original structure) so console-provided data verifies successfully.