feat: add isValueSnappingDisabled to NumberField

[will-stone]

As discussed here: #8776

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

1. Open the Step3WithMin2Max21ValueSnappingDisabled story.
2. Enter a value that's either under min, over max, or a wrong step.
3. Blur the input.
4. Notice the onChange callback fires with the same value you entered, and the input does not auto-snap to a valid number.

🧢 Your Project:

This will be used in an e-commerce situation where the NumberField is used for product quantity. Snapping is dangerous, for us, because a customer may not know that the number has been auto-healed, causing them to order less or more of what they need. I work for RS Group, and RAC powers our component library: ion. The component in question isn't live yet, but the RAC implementation is to replace our QuantityStepper component.

[will-stone]

Happy to have a stab at the docs but I'd like to please know if this is something you'd consider adding first 🙏 😅

[LFDanLu]

@will-stone interesting, this went a bit of a different route than I was expecting but I suppose native number type input fields do behave the same way. @snowystinger Any opinions here? Do you remember any reasons we didn't go this route in the first place?