fixup! Convert ConfirmationView form UIKit to SwiftUI

This PR is experimental, yet important first step towards transitioning
to SwiftUI. ConfirmationView has been rewritten entirely in SwiftUI. The
primary motivator for this PR was the frustrating nature of UIKit constraints.

Key factors to keep in mind while reviewing:

1. Checkmark image has been made smaller, which was the request from the
design team

2. UIFont does not translate 1:1 to SwiftUI Font, meaning the same font
looks just a little big different now. But dynamic scaling works, and all
our default fonts translate to expected outcome (font size, weight etc.)

3. Some approaches used in view layouts is due to the restrictions of
SwiftUI 1.0 capabilities. Those can and will be upgraded in the future

4. The naming of Views, and Objects, as well as file locations in the
directory are up for discussion. Everyone's input is much appreciated.

5. Prefix SwiftUI is used in lots of places due to a conflict with existing
custom objects Button and Image

6. New HeaderSwiftUI view does not include all the possible configuration
possibilities, as confirmations view's needs are not very demanding. So,
that view can be upgraded in future.

This PR also covers the ticket MOB-2488 which focuses on ADA-compliance
in ConfigurationsView

GliaWidgets/SecureConversations/Confirmation/SecureConversations.ConfirmationViewModel.swift

@@ -1,7 +1,7 @@
 import Foundation
 
 extension SecureConversations.ConfirmationViewSwiftUI {
-    class Model: ObservableObject {
+    final class Model: ObservableObject {
         let orientation: OrientationManager
         let style: SecureConversations.ConfirmationStyle
         var delegate: ((DelegateEvent) -> Void)?

GliaWidgets/SwiftUI/Components/Buttons/ActionButtonSwiftUI.swift

@@ -33,7 +33,7 @@ struct ActionButtonSwiftUI: View {
 }
 
 extension ActionButtonSwiftUI {
-    class Model: ObservableObject {
+    final class Model: ObservableObject {
         let style: ActionButtonStyle
         let height: CGFloat
         let tap: Cmd

GliaWidgets/SwiftUI/Components/Buttons/HeaderButtonSwiftUI.swift

@@ -29,7 +29,7 @@ struct HeaderButtonSwiftUI: View {
 }
 
 extension HeaderButtonSwiftUI {
-    class Model: ObservableObject {
+    final class Model: ObservableObject {
         var tap: Cmd
         var style: HeaderButtonStyle
         var size: CGSize

GliaWidgets/SwiftUI/Components/Header/HeaderSwiftUI.swift

@@ -47,7 +47,7 @@ struct HeaderSwiftUI: View {
 }
 
 extension HeaderSwiftUI {
-    class Model: ObservableObject {
+    final class Model: ObservableObject {
         let title: String
         let effect: Effect
         let endButton: ActionButtonSwiftUI.Model