Remove default upgrade-insecure-requests

Co-authored-by: Mike Lewis <mtlewis@users.noreply.github.com>
Co-authored-by: Himanshu Mishra <himanshu@orkohunter.net>
Signed-off-by: Tim Hansen <timbonicus@gmail.com>

contrib/docs/tutorials/help-im-behind-a-corporate-proxy.md

@@ -80,6 +80,4 @@ backend:
     origin: https://your-public-url.com:3000
 ```
 
-If the protocol is `http`, you will need to set `backend.csp.upgrade-insecure-requests` to `false` as well.
-
 The app port must proxy web socket connections in order to make hot reloading work.