Add static typing to the FocusZoneNativeComponent defaultTabbableElement type for Fabric usage#3864

PPatBoyd merged 2 commits intomicrosoft:mainmicrosoft/fluentui-react-native:mainfrom

PPatBoyd:focusZoneFabricDefaultTabbableIDPPatBoyd/fluentui-react-native:focusZoneFabricDefaultTabbableIDCopy head branch name to clipboard