Slider manipulation results in crashes for react-native-windows when no step is specified

[chrisfromwork]

Environment

• Building on a PC with visual studio 2019
• Using react-native-windows@0.64.0-preview.5
• Using @react-native-community/slider@4.0.0-rc.2

Description

If you don't specify a step value, no default is set. This then causes xaml range value component to generate errors

Reproducible Demo

• Setup a react-native-windows project
• Add @react-native-community/slider@4.0.0-rc.2 as a dependency and register the package in your project's app.cpp file
• Add a slider to your app, avoid specifying a step value
• Manipulate the slider

Observed behavior

The application crashes because no step value is set

Expected behavior

The application falls back to using a default step value

[rectified95]

fyi @BartoszKlonowski I already have a fix

[BartoszKlonowski]

@rectified95 I didn't notice your comment, but why have you been working on an issue which has already a developer assigned to it?

[rectified95]

Sorry about the confusion @BartoszKlonowski !
The issue was spotted by a consumer from Hololens. along with the autolinking problem. He first reached out to me and only created these issues for tracking/visibility after we figured out the problem offline.

I don't have the privileges to assign issues in this repo, so couldn't self-assign, but still wanted to fix the initial implementation I contributed here :) I remembered seeing this intermittently in the past, but thought I included the fix with the original PR. Later on I didn't check that you had it on you. We also wanted to fix it sooner than later so I just went ahead and did it.