4.1.2 enables sparse-checkout on builds that didn't ask for it

[bewinsnw]

Since the release of 4.1.2 30 minutes ago our builds with action/checkout@v4 have been failing on this action with:

git: 'sparse-checkout' is not a git command. See 'git --help'

On the self-hosted runner:
~$ git --version
git version 2.25.1

I can see from aadec89 that this was not intended with this release - so that commit can't be working correctly?

[bewinsnw]

closing as dupe of #1651 - beaten to the punch