fix(plugin-npm): normalize registry

[merceyz]

What's the problem this PR addresses?

While working on #5581 I noticed that we're not normalizing the registry passed to the npmHttpUtils methods.
There are tests that are supposed to catch this but the mock wasn't reset before each test so they didn't.

How did you fix it?

Normalize the registry and update the tests to use wrapNetworkRequest.

Checklist

• I have read the Contributing Guide.
• I have set the packages that need to be released for my changes to be effective.
• I will check that all automated PR checks pass before the PR gets reviewed.