Server URL resets when changing language on login

[aaronraimist]

• Changing language on login screen causes all the input on screen to be lost
  Seems like a lot of people are going to type in their login details first and then see the language selector
• Also switching from login to register causes the server URL to be lost, would be nice if this was saved across both screens (tracked by After setting a custom HS in sign-in, going to create account reverts it to matrix.org #8695)

Related: #7586

[jryans]

• Also switching from login to register causes the server URL to be lost, would be nice if this was saved across both screens

This bit is tracked by #8695, so let's refocus this to just the language part.

[jryans]

Changing the language currently causes a reload (we don't track the individual strings via React at the moment, so we use a reload to re-render). We don't save auth state across reloads currently, but we could... So far though, I am not convinced this is actually that common of an issue. I'd like to wait and see if other people are hitting this as well first.

[aaronraimist]

@jryans #11506 is probably caused by the same thing and happens much more frequently

[aaronraimist]

Related: #17525