Improve error handling in transferCrossChain command

[ishantiw]

Description

The token module throws error messages that are duplicated in multiple parts of the code. For example errors related to lack of account balance are repeated in /token/commands/transfer.ts#L57, /token/internal_method.ts#L78, token/commands/transfer_cross_chain.ts#L113, and /token/commands/transfer_cross_chain.ts#L158. Instead of hardcoding the same error message in many locations, consider creating a custom exception that receives the necessary parameters (e.g. sender address, amount) and creates the error message. Then at each location throw the custom exception.

Which version(s) does this affect? (Environment, OS, etc...)

v6.0.0-beta.2