Crash when username does not exist

[PabloCastellano]

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Issue Summary

Error 500 is returned, see traceback below. It should return 404 as https://CALENDSO_URI/unexisting/ does.

TypeError: Cannot read property 'id' of null
    at getServerSideProps (/home/pablo/calendso/.next/server/pages/[user]/[type].js:2974:20)
    at processTicksAndRejections (internal/process/task_queues.js:93:5)
    at async renderToHTML (/home/pablo/calendso/node_modules/next/dist/next-server/server/render.js:40:215)
    at async /home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:111:97
    at async /home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:104:142
    at async Server.renderToHTMLWithComponents (/home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:136:387)
    at async Server.renderToHTML (/home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:137:1088)
    at async Server.render (/home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:74:255)
    at async Object.fn (/home/pablo/calendso/node_modules/next/dist/next-server/server/next-server.js:58:672)
    at async Router.execute (/home/pablo/calendso/node_modules/next/dist/next-server/server/router.js:25:67)

Steps to Reproduce

1. Go to https://CALENDSO_URI/unexisting/type

Technical details

• Browser Firefox
• Node.js 14.16