Bug - Number Input - cannot type negative values

[jenny-s51]

Describe the problem
A clear and concise description of the problem. Which components are affected?
User cannot type negative values into the number input component. At the moment the "$" example of "With Unit" is the only number input that supports typing negative values - this example works consistently among the staging website and the live docs.

Staging:
https://patternfly-react-main.surge.sh/components/number-input/

Current:
https://www.patternfly.org/v4/components/number-input

How do you reproduce the problem?
Provide steps to reproduce. A codesandbox demonstrating the problem is appreciated.

1. Go to the staging website
2. Type a negative value into default, it should work.
3. Update any of the other number input demos with any value.
4. Try to type another negative value into default; it no longer supports typing a -.
5. Go to the current pf4 docs website
6. Try typing a negative value into default, it does not work.

Expected behavior
A clear and concise description of the expected behavior.
Typing negative values should be supported. Currently it is only possible to have negative numbers by clicking the - button on the left of the input field.

cc @tlabaj

[MrVSiK]

If I understand it correctly, the issue exists with the keyDownHandler in https://github.com/patternfly/patternfly-react/blob/main/packages/react-core/src/components/NumberInput/NumberInput.tsx. I'd like to work on it, assuming it has not been fixed already?

[CodeDuchess]

@nicolethoen I can work this ticket. Thanks.