This diff removes minimal-slp-wallet from the package dependencies and reverts to calling it from the unpkg CDN. In testing, it seems like this dependency is causing the long white screen before load issue.
It's important to include minimal-slp-wallet for the chrome extension (vs hosted dependency), but not for the web app. So, another diff will follow to bump the extension version with latest features and keep this dependency for the extension only.
This diff also updates antd/icons to the latest version, which is smaller.
During testing, I discovered an important edge case bug, and included it in this diff because I think it needs to be patched ASAP and is not a complicated change. See the haveUtxosChanged function modification in useWallet.js