VG-750 VG-9256 VG-6129 fix(explorer): Return explorer error in broadcast error message

[BertrandD]

Fixes VG-750 Fixes VG-9256 Fixes VG-6129

Fix to have explorer error message in WD's response

Previously we had:

{
    "type": "Internal_Error",
    "message": {
        "response": "Internal server error occurred while processing the request. Bad Request"
    }
}

Now we have:

{
    "type": "Internal_Error",
    "message": {
        "response": "Internal server error occurred while processing the request. Got explorer error: -25: bad-txns-inputs-missingorspent"
    }
}

[github-actions[bot]]

clang-tidy review says "All clean, LGTM! :+1:"