Don't set accessibilityRole by default in Flatlist

[chiuam]

Please select one of the following

• I am removing an existing difference between facebook/react-native and microsoft/react-native-macos 👍
• I am cherry-picking a change from Facebook's react-native into microsoft/react-native-macos 👍
• I am making a fix / change for the macOS implementation of react-native
• I am making a change required for Microsoft usage of react-native

Summary

Reverting 6ad34ef which broke Android. When updateViewProp gets called, the value "table" for the accessibilityRole prop is not recognized on Android. See the list of valid props for accessibilityRole here. iOS handles "table" as no-op since it's mapped to UIAccessibilityTraitNone.

Note: This implies that clients need to manually set the prop to get the accessibility effects.

Changelog

[Fixed] [macOS] - Don't set accessibilityRole by default in Flatlist

Test Plan

1. Flatlist VO works as expected on macOS.
2. Flatlist boots on iOS.