Reproduction steps:
1. Open the attached user's project "BugInputSystemDeadzone.zip"
2. In the Project window under the "Assets" folder open "MyControls.inputactions"
3. On the right side Properties window under the Processors dropdown uncheck the Default Minimum Axis Deadzone
4. Set the Minimum Axis Deadzone to 0 and save it
5. Open the saved asset

Expected result: Min Axis Deadzone does not fallback to the Default value if 0 is set as a Min value
Actual result: Min Axis Deadzone fallbacks to the Default value if 0 is set as a Min value (see attached InputSystemDeadzone.mp4)

Reproduces on: Input System 1.0.0 - preview.2, 1.1.0 - Preview.2 (2019.4.15f1, 2020.1.15f1, 2020.2.0b12, 2021.1.0a7)
Could not test on Input System 0.2.1 (2018.4.29f1) due to no Default option available for Minimum Deadzone in Input Actions Processors Window

Notes:
- This feature was introduced in Input System 1.0.0 - preview.2, below this version there is no Default option available for Minimum Deadzone in Input Actions Processors Window