FireblocksApiException does not contain the error code

[selevit]

When getting a 4xx or 5xx response, the sdk raises FireblocksApiException, with the following args:

('Got an error from fireblocks server: {"message":"The external tx id that was provided in the request, already exists","code":1438}',)

Error code is presented inside the error message, which is tricky to parse and extract. Would be great to have the error_code integer property in FireblocksApiException.

[yarinvak]

included in v1.9.0 thanks for the suggestion