[web][lib][landing] Prevent crash when missing WalletConnect key

Summary: See ENG-4175 for context.

Test Plan: I moved my keyserver/secrets/walletconnect.json file to another path. Without this diff the web app was crashing, but after this diff it was able to load successfully.

Reviewers: kamil, atul

Reviewed By: kamil

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8349