[debug] evaluate response should properly represent error / failure

[ptrthomas]

as of today this is how the evaluate command is handled: https://github.com/karatelabs/karate/blob/v1.2.1.RC1/karate-core/src/main/java/com/intuit/karate/debug/DapServerHandler.java#L331

we need to use the ErrorResponse for better IDE user-experience: https://microsoft.github.io/debug-adapter-protocol/specification#Base_Protocol_ErrorResponse