Add SwiftLint rule to enforce stack spacing. (#2080)

Xcode 15 changes the default behaviour and given we're always working from designs, we shouldn't rely on it for our layout.

ElementX/Sources/Other/SwiftUI/Animation/ShimmerModifier.swift

@@ -87,7 +87,7 @@ struct ShimmerOverlay_Previews: PreviewProvider, TestablePreview {
                                                userIndicatorController: ServiceLocator.shared.userIndicatorController)
     
     static var previews: some View {
-        VStack {
+        VStack(spacing: 0) {
             ForEach(0...8, id: \.self) { _ in
                 HomeScreenRoomCell(room: .placeholder(), context: viewModel.context, isSelected: false)
             }

ElementX/Sources/Other/SwiftUI/Form Styles/FormButtonStyles.swift

@@ -97,7 +97,7 @@ struct FormButtonStyle: PrimitiveButtonStyle {
         var accessory: FormRowAccessory?
         
         func makeBody(configuration: Configuration) -> some View {
-            HStack {
+            HStack(spacing: 8) {
                 configuration.label
                     .labelStyle(FormRowLabelStyle(role: configuration.role))
                     .foregroundColor(.compound.textPrimary)
@@ -126,7 +126,7 @@ struct FormActionButtonStyle: ButtonStyle {
     let title: String
     
     func makeBody(configuration: Configuration) -> some View {
-        VStack {
+        VStack(spacing: 8) {
             configuration.label
                 .buttonStyle(.plain)
                 .foregroundColor(.compound.textPrimary)

ElementX/Sources/Other/SwiftUI/Form Styles/FormRowLabelStyle.swift

@@ -61,7 +61,7 @@ struct FormRowLabelStyle: LabelStyle {
 
 struct FormRowLabelStyle_Previews: PreviewProvider, TestablePreview {
     static var previews: some View {
-        VStack(alignment: .leading) {
+        VStack(alignment: .leading, spacing: 12) {
             Label("Person", systemImage: "person")
                 .labelStyle(FormRowLabelStyle())
             

ElementX/Sources/Other/SwiftUI/Layout/FullscreenDialog.swift

@@ -50,7 +50,7 @@ struct FullscreenDialog<Content: View, BottomContent: View>: View {
     var standardLayout: some View {
         GeometryReader { geometry in
             ScrollView {
-                VStack {
+                VStack(spacing: 0) {
                     Spacer()
                         .frame(height: UIConstants.spacerHeight(in: geometry))
                     
@@ -62,7 +62,7 @@ struct FullscreenDialog<Content: View, BottomContent: View>: View {
             }
             .scrollBounceBehavior(.basedOnSize)
             .safeAreaInset(edge: .bottom) {
-                VStack {
+                VStack(spacing: 0) {
                     bottomContent()
                         .readableFrame()
                         .padding(.horizontal, horizontalPadding)
@@ -81,7 +81,7 @@ struct FullscreenDialog<Content: View, BottomContent: View>: View {
     var accessibilityLayout: some View {
         GeometryReader { geometry in
             ScrollView {
-                VStack {
+                VStack(spacing: 0) {
                     Spacer()
                         .frame(height: UIConstants.spacerHeight(in: geometry))