`ServerTypeSelector` would call its `onChange` prop both at construction
(because it computed the default selected type and consumers might want to know)
as well as on actual user change. This ended up complicating consumer code, as
they want to differentiate between initial state and changes made by the user.
To simplify things, `ServerTypeSelector` now exports a function to compute the
server type from HS URL, which can be useful for setting its initially selected
type. The consumer now provides that type via a prop, and `onChange` is now only
called for actual user changes, simplifying the logic in `Registration` which
uses `ServerTypeSelector`.
In addition, some usages of `customHsUrl` vs. `defaultHsUrl` in `Registration`
are simplified to be `customHsUrl` only (since it already includes a fallback to
the default URL in `MatrixChat`).
We weren't correctly jumping into the appropriate bit of the registration
flow when coming in from an email link.
* If we have client secret / sessionId, go straight to registration phase
* Don't reset server URLs when the server type component tells us its
initial value
* Confusingly, pass the custom server URL as 'default server URL' to
the custom server type, as this is what we want the inital section
to be based on.
Fixes https://github.com/vector-im/riot-web/issues/8490
This changes the auth screens to use the modal-like style of the redesign.
This does not attempt to style the actual body content of each screen. Instead,
it covers the header area with logo, footer links, and overall modal container
only.
