cli: resume commiting on the next run after a pre-commit task fails

[hasundue]

Suppose:

1. You run molt --commit --pre-commit test
2. Test failed on updates to one of the dependencies
3. You fixed the code to pass tests
4. You run molt --commit --pre-commit test again with those uncommitted changes

Then the CLI ignores the changes and just tries to commit updates to the other dependencies, which is awkward.