Add support for Account Provisioning links. (#4108)

* Add support for account provisioning links and route them to the authentication flow.

* Use the provisioning parameters to configure the authentication flow.

* Add UI tests for the provisioned authentication flow.

* Record new preview snapshots.

* Add unit tests.

* Make the domain configurable in the app settings.

* Use the loginHint in the login screen too.

ElementX/Sources/Services/Authentication/AuthenticationService.swift

@@ -82,13 +82,14 @@ class AuthenticationService: AuthenticationServiceProtocol {
         }
     }
     
-    func urlForOIDCLogin() async -> Result<OIDCAuthorizationDataProxy, AuthenticationServiceError> {
+    func urlForOIDCLogin(loginHint: String?) async -> Result<OIDCAuthorizationDataProxy, AuthenticationServiceError> {
         guard let client else { return .failure(.oidcError(.urlFailure)) }
         do {
             // The create prompt is broken: https://github.com/element-hq/matrix-authentication-service/issues/3429
             // let prompt: OidcPrompt = flow == .register ? .create : .consent
             let oidcData = try await client.urlForOidc(oidcConfiguration: appSettings.oidcConfiguration.rustValue,
-                                                       prompt: .consent)
+                                                       prompt: .consent,
+                                                       loginHint: loginHint)
             return .success(OIDCAuthorizationDataProxy(underlyingData: oidcData))
         } catch {
             MXLog.error("Failed to get URL for OIDC login: \(error)")