chore(ntx-builder): attach sponsorship notes error to feature notes

[SantiagoPittella]

closes #2515

Summary

Attaches the sponsorship notes error to the feature note, to be returned when calling to GetNetworkNoteStatus. THe response is now structured as:

// Response containing the lifecycle status and latest execution error for a network note.
message GetNetworkNoteStatusResponse {
    // Current lifecycle status of the note.
    NetworkNoteStatus status = 1;
    // The latest error message from execution, if any.
    optional string last_error = 2;
    // Number of failed execution attempts.
    uint32 attempt_count = 3;
    // Block number of the last failed attempt, if any.
    optional fixed32 last_attempt_block_num = 4;
    // FEE_SPONSORSHIP notes bound to this note.
    repeated NetworkNoteSponsorship sponsorships = 5;
}

// A FEE_SPONSORSHIP note that pays the fee for a network note.
message NetworkNoteSponsorship {
    // ID of the sponsorship note.
    note.NoteId note_id = 1;
    // Fee asset that the sponsorship note carries.
    asset.Asset fee_asset = 2;
    // Block height at or after which the reclaimer can reclaim the note. Not set when reclaim is
    // disabled.
    optional fixed32 reclaim_height = 3;
    // Block number in which the sponsorship note was consumed. Not set while it is unconsumed.
    optional fixed32 committed_block_num = 4;
    // The latest execution error of the sponsorship note, if any.
    optional string last_error = 5;
    // Block number of the last failed attempt of the sponsorship note, if any.
    optional fixed32 last_attempt_block_num = 6;
}

Changelog

[[entry]]
scope       = "rpc"
impact      = "added"
description = "`GetNetworkNoteStatus` now lists the `FEE_SPONSORSHIP` notes bound to the note, with their fee asset, reclaim height, consuming block, and latest execution error."

[[entry]]
scope       = "ntx-builder"
impact      = "changed"
description = "When a `FEE_SPONSORSHIP` note fails, the feature note's `last_error` now names the failed sponsorship note."