Fix ReferenceError in publish.js

[jtbandes]

In this workflow run, a 404 error was encountered, but this was followed by a ReferenceError because error is not defined in this file.

npm error code E404
npm error 404 Not Found - PUT https://registry.npmjs.org/@xterm%2fxterm - Not found
npm error 404
npm error 404  '@xterm/xterm@5.6.0-beta.71' is not in this registry.
npm error 404
npm error 404 Note that you can also install from a
npm error 404 tarball, folder, http url, or git url.
npm error A complete log of this run can be found in: /home/runner/.npm/_logs/2024-12-12T14_38_06_501Z-debug-0.log
/home/runner/work/xterm.js/xterm.js/bin/publish.js:117
    error(`Spawn exited with code ${result.status}`);
    ^

ReferenceError: error is not defined
    at checkAndPublishPackage (/home/runner/work/xterm.js/xterm.js/bin/publish.js:117:5)
    at Object.<anonymous> (/home/runner/work/xterm.js/xterm.js/bin/publish.js:33:16)
    at Module._compile (node:internal/modules/cjs/loader:1364:14)
    at Module._extensions..js (node:internal/modules/cjs/loader:1422:10)
    at Module.load (node:internal/modules/cjs/loader:1203:32)
    at Module._load (node:internal/modules/cjs/loader:1019:12)
    at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:128:12)
    at node:internal/main/run_main_module:28:49

[jtbandes]

I'm assuming that exiting with the same status code is not too important, because the child process's status code is part of the error message already?