Missing support for preClose application hook

[knolleary]

If this module is used with a fastify plugin that uses the preClose application hook, the app will fail to start:

/Users/nol/code/ff/flowforge-dev-env/node_modules/fastify-overview/index.js:184
    this[kStructure].hooks[name].push(hookNode)
                                 ^

TypeError: Cannot read properties of undefined (reading 'push')
    at Object.wrapAddHook [as addHook] (/Users/nol/code/ff/flowforge-dev-env/node_modules/fastify-overview/index.js:184:34)
    at fastifyWebsocket (/Users/nol/code/ff/flowforge-dev-env/node_modules/@fastify/websocket/index.js:151:11)
    at Plugin.exec (/Users/nol/code/ff/flowforge-dev-env/node_modules/avvio/plugin.js:130:19)
    at Boot.loadPlugin (/Users/nol/code/ff/flowforge-dev-env/node_modules/avvio/plugin.js:272:10)

In this example we are using @fastify/websocket which uses the preClose hook.

I believe the root cause is preClose is missing from the object returned by getEmptyHookApplication

fastify-overview/lib/utils.js

Line 88 in 3555df2

function getEmptyHookApplication () {

If I can figure out how the tests are structured, I'll see if I can PR a fix.