setting up remote-upstream through ncu

I am on a new laptop and forgot some configs in my project specific config and failed the cq due to column length > 72 characters, therefore decided to land the PR manual by using core-util.

Followed the steps to:

pre: installed @node-core/utils through npm

1. create a scoped token
2. put token into ~/.ncurc
3. run git node land 57732
4. followed the prompt to setup remote-url and branch main to main

➜  node git:(add-lower-bound-range-test) ✗ ncu-config list
branch: main
upstream: remote-upstream

and then I encountered the following error message:

    at runSync (file:///Users/jake/.nvm/versions/node/v23.11.0/lib/node_modules/@node-core/utils/lib/run.js:109:11)
    at new Session (file:///Users/jake/.nvm/versions/node/v23.11.0/lib/node_modules/@node-core/utils/lib/session.js:30:28)
    at new LandingSession (file:///Users/jake/.nvm/versions/node/v23.11.0/lib/node_modules/@node-core/utils/lib/landing_session.js:24:5)
    at main (file:///Users/jake/.nvm/versions/node/v23.11.0/lib/node_modules/@node-core/utils/components/git/land.js:171:17)

I think it is trying to find remote-upstream as after I did git remote add remote-upstream https://github.com/nodejs/node.git the issue was resolved. However, this confused me for a few minutes, shouldn't it default to just upstream or attempt to add remote-upstream for the user automatically?

Reproduce the failure using the reported ncu-config list and git node land flow, then start in components/git/land.js and lib/landing_session.js, with the command runner in lib/run.js. Check how the configured remote-upstream is resolved when it is absent, and define done as handling that missing remote consistently with the intended upstream behavior and covering the result with a test.