More verbose error message when calling transition

[charliecys]

This could be helpful for create transaction as well.

Current SDK error message is just writing
not checksum Address or bech32panic: runtime error: invalid memory address or nil pointer dereference

It could be more verbose in stating which field does not conform to the requirement (checksum address/bech32)

Note: I encountered this while trying to trigger a contract transition and it turned out that I need to change the contract address to a checksum address.

[renlulu]

Okay, will do it soon.