build: Update Vue to 3.2.27 and VitePress to 0.21.6

Because one of VitePress's new dependencies pulls in @types/react, we
need to fix some things in the TypeScript config to keep vue-tsc happy.

Also fix the use of Object.values() on an array in Button.test.ts.

Change-Id: I7d77f43d6aab8ca45906423fefa6ff6d867a21a0