errorHandling when 404 from getAccountInfo

[decentraliser]

all latest

When hitting accountHttp.getAccountInfo, for an unknown account, the error is thrown badly because the error is not within body, and it doesn't get stringified

https://github.com/nemtech/nem2-sdk-typescript-javascript/blob/71e41cde6afec5dc82522ea2f86516dd06cbe54a/src/infrastructure/Http.ts#L61

[44uk]

I met inconvenience error when account is not found.

Error: [object Object]