[BUG] `npm install --package-lock-only` does not imply `--package-lock`

### Current Behavior:
put `package-lock=false` in `.npmrc`.

Run `npm install --package-lock-only`.

### Expected Behavior:
a package-lock.json is generated.

### Steps To Reproduce:
See above.

### Environment:
- npm: 7.5.4

This is a regression from https://github.com/npm/cli/pull/146 / v6.9.0.

(possibly related to #2358)