[Portal] No 404 for invalid path in URL

## Background:
Device / Browser (OS version): Chrome on Mac, Safari on Mac, Firefox on Mac
Build: staging-2023-02-17.0

## Description:
In portal, there is No 404 for invalid path in URL

## Steps:

1. Go to https://portal.authgear-staging.com/asdfqwerty or any invalid path
2. See page responded with a loading wheel and then a white page.

## Expected:
Should show 404 with no loading, as loading conveys that it is a valid path.

## Screenshot: