Convert Seammammals plugin to Sandy {emoji:1f389}

Summary:
Converted the Seammammals plugin to use Sandy plugin infra (but the old components). Also updated lock file.

Added unittests have been added as well. The UI snapshots in there are kinda overkill, but nice demo that it works.

This completes the full roundtrip of the new Sandy infra, so this will be the last diff of this stack. I promise. I think.

Reviewed By: nikoant

Differential Revision: D22308265

fbshipit-source-id: 260e91a1951d486f6689880fe25281e80a71806a

desktop/flipper-plugin/src/__tests__/TestPlugin.tsx

@@ -77,6 +77,5 @@ export function Component() {
   // @ts-expect-error
   api.bla;
 
-  // TODO N.b.: state updates won't be visible
   return <h1>Hi from test plugin {count}</h1>;
 }