[chore] remove unecessary prefix

[halink0803]

Solana return the response under the structure of

{
  "code":-32009,
  "message":"Slot 135999228 was skipped, or missing in long-term storage",
  "data":null
}

Adding unnecessary prefix make it impossible to parse the error response to object and hard to check the error. Remove the prefix make is easier to work with error response.

[yihau]

Thanks for the feedback. Just open a PR #97, I think it can solve this problem. IMO, I prefer to return the error directly instead of have a custom function to parse it. wdyt?

[halink0803]

Thanks for the feedback. Just open a PR #97, I think it can solve this problem. IMO, I prefer to return the error directly instead of have a custom function to parse it. wdyt?

Yes, I also prefer to have the error return directly.