Fix potential crash with invalid attachment aspect ratio

Tusker/Views/Attachments/AttachmentsContainerView.swift

@@ -295,7 +295,11 @@ class AttachmentsContainerView: UIView {
                 accessibilityElements.append(moreView)
             }
             
-            self.aspectRatio = aspectRatio
+            self.aspectRatio = if aspectRatio.isNaN || aspectRatio.isInfinite {
+                16/9
+            } else {
+                aspectRatio
+            }
         } else {
             self.isHidden = true
         }