assert break the contract, maybe provide another helper utils to response the error back to frontend?

[HelloRWA]

currently we use the assert

  assert(type(to) == 'string', "to is required!")

this will break the lua contract, and from frontend just get the error in a console format with color code, some kind like this:

in function '.process.handle'\u001b[0m\n\n\u001b[31merror:\n\u001b[0m[string \".handlers\"]:559: [string \"aos\"]:138: to is required!"

maybe we can have another field like rawError and can append into the response for frontend?

{
    ... the same as old output response,
   "rawError": "to is requred!"
}