project deploy start --json missing information with failing tests

[WillieRuemmele]

Summary

similar to #2757

when validating a deployment, test failures are not reported in --json output

sf project deploy validate -l RunSpecifiedTests -t  testtest12   --source-dir force-app  --json
 ›   Warning: @salesforce/cli update available from 2.45.6 to 2.48.6.
{
  "code": 1,
  "context": "DeployMetadataValidate",
  "commandName": "DeployMetadataValidate",
  "data": {
    "deployId": "0AfdL000004QTP3SAO"
  },
  "message": "Failed to validate the deployment (0AfdL000004QTP3SAO). Due To:\n",
  "name": "FailedValidationError",
  "status": 1,
  "stack": "FailedValidationError: Failed to validate the deployment (0AfdL000004QTP3SAO). Due To:\n\n    at Messages.createError (/Users/shivanshu.tiwari/.local/share/sf/client/2.45.6-

whereas without --json

Validating Deployment of v61.0 metadata to XXX using the v61.0 SOAP API.
Deploy ID: 0AfdL000004QTDlSAO
Status: Failed | ████████████████████████████████████████ | 2/2 Components | 0/1 Tests(Errors:1)
Test Failures [1]
• testtest12.TestNewFileInserted
  message: System.DmlException: Insert failed. First exception on row 0; first error: CANNOT_INSERT_UPDATE_ACTIVATE_ENTITY, tes23425632.test12: execution of BeforeInsert

Steps To Reproduce

with the following test class

@isTest
private class testtest12 {
    @isTest
    static void TestNewFileInserted() {
        Test.startTest();
        Account accA = new Account(Name = 'File Test');
        insert accA;

        Case caseA = new Case(
            AccountId = accA.Id,
            Status = 'New',
            Subject = 'File Test',
            Description = 'File Test',
            Origin = 'Email'
        );
        insert caseA;
        insert caseA;

        
        ContentVersion content = new ContentVersion();
        content.Title = 'Header_Picture1';
        content.PathOnClient = '/' + content.Title + '.jpg';
        Blob bodyBlob = Blob.valueOf('Unit Test ContentVersion Body');
        content.VersionData = bodyBlob;
        insert content;
        ContentDocumentLink contentlink = new ContentDocumentLink();
        contentlink.LinkedEntityId = caseA.id;
        contentlink.contentdocumentid = [
            SELECT contentdocumentid
            FROM contentversion
            WHERE id = :content.id
        ]
        .contentdocumentid;

        insert contentlink;
        Test.stopTest();
    }
}

Expected result

json would include information about test failure/DML exception like stdout has

Actual result

stack trace only

System Information

bash/macos

{
  "architecture": "darwin-arm64",
  "cliVersion": "@salesforce/cli/2.50.5",
  "nodeVersion": "node-v21.1.0",
  "osVersion": "Darwin 23.5.0",
  "rootPath": "/Users/william.ruemmele/.nvm/versions/node/v20.12.2/lib/node_modules/@salesforce/cli",
  "shell": "zsh",
  "pluginVersions": [
    "@oclif/plugin-autocomplete 3.1.6 (core)",
    "@oclif/plugin-commands 4.0.6 (core)",
    "@oclif/plugin-help 6.2.5 (core)",
    "@oclif/plugin-not-found 3.2.10 (core)",
    "@oclif/plugin-plugins 5.3.4 (core)",
    "@oclif/plugin-search 1.2.2 (core)",
    "@oclif/plugin-update 4.4.7 (core)",
    "@oclif/plugin-version 2.2.6 (core)",
    "@oclif/plugin-warn-if-update-available 3.1.8 (core)",
    "@oclif/plugin-which 3.2.6 (core)",
    "@salesforce/cli 2.50.5 (core)",
    "apex 3.2.4 (core)",
    "auth 3.6.33 (core)",
    "data 3.5.5 (core)",
    "deploy-retrieve 3.9.13 (core)",
    "info 3.3.17 (core)",
    "limits 3.3.17 (core)",
    "marketplace 1.2.17 (core)",
    "org 4.3.4 (core)",
    "packaging 2.7.0 (core)",
    "schema 3.3.19 (core)",
    "settings 2.3.8 (core)",
    "sobject 1.4.19 (core)",
    "source 3.5.3 (core)",
    "telemetry 3.6.1 (core)",
    "templates 56.3.2 (core)",
    "trust 3.7.13 (core)",
    "user 3.5.17 (core)"
  ]
}

Additional information

[git2gus]

This issue has been linked to a new work item: W-16198239