fix: prevent double-swap ping-pong during relay drag

After swapping with an adjacent item, the dragOffset adjustment can
flip its sign (e.g. negative becomes positive), which immediately
triggers the second if-block to swap back in the opposite direction
within the same onDrag call. This causes the dragged item to jump
and the user to end up dragging a different item. Fix by returning
after each successful swap so only one swap occurs per drag event.

https://claude.ai/code/session_01RVM5kEJGrCaJTaP3GmVHDd

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/relays/common/DraggableRelayList.kt

@@ -71,6 +71,7 @@ class RelayDragState(
 
                 dragOffset += aboveHeight
                 draggedItemIndex = currentIndex - 1
+                return
             }
         }
 
@@ -87,6 +88,7 @@ class RelayDragState(
 
                 dragOffset -= belowHeight
                 draggedItemIndex = currentIndex + 1
+                return
             }
         }
     }