CLI: Fix local repro publishing

[shilman]

Issue: N/A

What I did

To publish using the local registry, always use NPM config.

How to test

In the vite-frameworks branch (which also has this change):

yarn generate-repros-next --template vue3-vite/default-js --local-registry

Before this will fail, after it will succeed

[yannbf]

LGTM though we should probably revisit this cc @ndelangen

[shilman]

@yannbf I looked at this with @ndelangen and we found:

• Setting the registry using yarn config works (we're not sure which setting works, since our code set a bunch of them)
• As soon as you use npm config, however, that will take priority

Based on this information, this PR seems to make sense, even though it feels a bit dirty. Merging for now until somebody comes up with a better solution.