fix: fix --json error output to remove color info @W-21312816@

[WillieRuemmele]

What does this PR do?

cleans up --json output

{
  "name": "CompileAgentScriptError",
  "message": "SyntaxError: Unexpected 'messaasdfges' [Ln 3, Col 4]",
  "exitCode": 1,
  "context": "AgentValidateAuthoringBundle",
  "data": {
    "errors": [
      {
        "errorType": "SyntaxError",
        "description": "Unexpected 'messaasdfges'",
        "lineStart": 3,
        "lineEnd": 3,
        "colStart": 4,
        "colEnd": 16
      }
    ]
  },

instead of

{
  "name": "Error",
  "message": "Compilation of the Agent Script file failed with the following errors:\n- \u001b[31mSyntaxError\u001b[39m: Unexpected 'messaasdfges' [Ln 3, Col 4]",
  "exitCode": 1,
  "context": "AgentValidateAuthoringBundle",
  "stack": "Error: Compilation of the Agent Script file failed with the following errors:\n- \u001b[31mSyntaxError\u001b[39m: Unexpected 'messaasdfges' [Ln 3, Col 4]\n    at SfCommandError.from (file:///Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/node_modules/@salesforce/sf-plugins-core/lib/SfCommandError.js:48:16)\n    at AgentValidateAuthoringBundle.catch (file:///Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/node_modules/@salesforce/sf-plugins-core/lib/sfCommand.js:332:47)\n    at AgentValidateAuthoringBundle._run (/Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/node_modules/@oclif/core/lib/command.js:186:29)\n    at process.processTicksAndRejections (node:internal/process/task_queues:103:5)\n    at async Config.runCommand (/Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/node_modules/@oclif/core/lib/config/config.js:456:25)\n    at async run (/Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/node_modules/@oclif/core/lib/main.js:97:16)\n    at async file:///Users/william.ruemmele/.nvm/versions/node/v24.12.0/lib/node_modules/@salesforce/cli/bin/run.js:15:1",
  "cause":

creates unified exit codes
requires: forcedotcom/agents#219

What issues does this PR fix or reference?

@W-21312816@