Add Email/Terms/ReCaptcha into the Authentication flow

Replace ReCaptcha navigation delegate with a WKUserContentController.
Move callback property closures onto the MainActor.
Show a loading indicator whilst waiting for the authentication service to start.
Move nextUncompletedStage into FlowResult.
Handle text field actions during authentication.
Remove scroll view tweaks in server selection screen following EMS banner removal.

RiotSwiftUI/Modules/Room/PollEditForm/View/PollEditFormAnswerOptionView.swift

@@ -38,7 +38,7 @@ struct PollEditFormAnswerOptionView: View {
                 TextField(VectorL10n.pollEditFormInputPlaceholder, text: $text, onEditingChanged: { edit in
                     self.focused = edit
                 })
-                .textFieldStyle(BorderedInputFieldStyle(theme: _theme, isEditing: focused))
+                .textFieldStyle(BorderedInputFieldStyle(isEditing: focused))
                 Button(action: onDelete) {
                     Image(uiImage:Asset.Images.pollDeleteOptionIcon.image)
                 }