Fixes #3173 - Force frame sizes for timeline items that are missing sizing info.

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

@@ -11,6 +11,7 @@ extension View {
     /// Constrains the max height of a media item in the timeline, whilst preserving its aspect ratio.
     @ViewBuilder
     func timelineMediaFrame(height contentHeight: CGFloat?, aspectRatio contentAspectRatio: CGFloat?) -> some View {
+        let defaultMediaSize = 100.0
         let minMediaHeight = 100.0
         let maxMediaHeight = 300.0
         
@@ -23,9 +24,8 @@ extension View {
                     .frame(maxHeight: min(maxMediaHeight, max(minMediaHeight, contentHeight ?? .infinity)))
                     // Required to prevent the reply details to get higher priority in rendering the width of the view.
                     .aspectRatio(contentAspectRatio, contentMode: .fit)
-            } else { // Otherwise let the image load and use its native aspect ratio with a max height
-                aspectRatio(contentMode: .fit)
-                    .frame(maxHeight: maxMediaHeight)
+            } else { // Otherwise force the image to be `defaultMediaSize` x `defaultMediaSize`
+                frame(width: defaultMediaSize, height: defaultMediaSize)
             }
         }
     }