Support fsevents watcher on Apple silicon

[robhogan]

Summary

If Watchman is unavailable or disabled, we try to fall back to FSEventsWatcher and then to NodeWatcher. FSEventsWatcher is only available on darwin, so we require it in a try/catch and swallow any error.

This was hiding the fact that fsevents was also failing to load on Apple silicon:

 dlopen(/Users/robhogan/gh/metro/node_modules/fsevents/fsevents.node, 0x0001): tried: '/Users/robhogan/gh/metro/node_modules/fsevents/fsevents.node' (mach-o file, but is an incompatible architecture (have (x86_64), need (arm64e)))

fsevents@2.3 introduces support for Apple silicon. This updates to that version, and also adds Flow types based on the TypeScript types bundled with fsevents so that Flow check passes on darwin (the Flow error was untyped-import so the existing cannot-resolve-module suppression doesn't work).

Test plan

After:

$ node packages/metro/src/cli serve -c ../dummyproj/metro.config.js

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                Welcome to Metro v0.72.3
              Fast - Scalable - Integrated


  Metro:FSEventsWatcher Watching /Users/robhogan/gh/dummyproj +0ms

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@robhogan has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.