Simplify how we build bubbles for previewing purposes, make use of the new bubbleBackground modifier.

ElementX/Sources/Screens/Timeline/View/Style/LongPressWithFeedback.swift

@@ -95,9 +95,7 @@ struct LongPressWithFeedback_Previews: PreviewProvider, TestablePreview {
         
         func mockBubble(_ body: String) -> some View {
             Text(body)
-                .padding(.horizontal, 12)
-                .padding(.vertical, 4)
-                .background(Color.compound._bgBubbleOutgoing, in: RoundedRectangle(cornerRadius: 12))
+                .bubbleBackground()
                 .contentShape(.contextMenuPreview, RoundedRectangle(cornerRadius: 12))
                 .onTapGesture { /* Fix long press gesture blocking the scroll view */ }
         }

ElementX/Sources/Screens/Timeline/View/Style/TimelineItemBubbleBackground.swift

@@ -5,12 +5,13 @@
 // Please see LICENSE in the repository root for full details.
 //
 
+import Compound
 import SwiftUI
 
 extension View {
-    func bubbleBackground(isOutgoing: Bool,
-                          insets: EdgeInsets,
-                          color: Color? = nil) -> some View {
+    func bubbleBackground(isOutgoing: Bool = true,
+                          insets: EdgeInsets = .init(top: 8, leading: 12, bottom: 8, trailing: 12),
+                          color: Color? = .compound.bgSubtleSecondary) -> some View {
         modifier(TimelineItemBubbleBackgroundModifier(isOutgoing: isOutgoing,
                                                       insets: insets,
                                                       color: color))