createRandomAlias should be based on the current selected hostname

[xairoo]

When you use the extension, you should be able to generate a random alias based on the current selected hostname, not on the default hostname.
It's weird to create a UUID and paste it into the extension if you don't want to use the default hostname.

https://github.com/simple-login/browser-extension/blob/b85c898a83b0bd652513151c302ad0e427ce5e55/src/popup/components/Main.vue#L464-L472

The hostname should be set when you change the hostname within the selector

https://github.com/simple-login/browser-extension/blob/b85c898a83b0bd652513151c302ad0e427ce5e55/src/popup/components/Main.vue#L48-L60

Also the API doc tells us:

(Optional but recommended) hostname passed in query string

And of course this is something that should be in the web version too.