[0.64] Add onFocus/onBlur/onKeyDown/onKeyUp to Pressable

[Saadnajmi]

Cherry pink #962 into 0.64-stable

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

Closes #518

Pressable was missing the onFocus/onBlur callbacks, I guess we missed this when we first added those props to Touchable. Let's go explicitly add them. I based my code off of the React Native Windows fork of Pressable.

In the future, I would also like to add Space/Enter keyboarding defaults to Pressable like React Native Windows has, where onKey(Down|Up) of Space/Enter on a Pressable is equivalent to onPress(In|Out). However, that would need me to make significant changes to how keyboard events work on macOS, so I'll just be sure to expose them now and leave it for later.

Changelog

[macOS] [Fixed] - Pressable didn't expose onFocus/onBlur

Test Plan

Added tests to rn-tester which indeed show onFocus/onBlur are fired.

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	Warnings
⚠️	🔒 package.json - Changes were made to package.json. This will require a manual import by a Facebook employee.

	Messages
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[Saadnajmi]

Closing till I get the CI in 0.64 in a better state