Non-op player in spawn protection can remove leash knot by right clicking it

The bug

After MC-862 has been fixed non-op players can still "destroy"/remove leash knots by simply right clicking them.

How to reproduce

1. Start a server

2. Op any player other than yourself (from the console) to activate spawn protection

   /op Notch

3. Op yourself (from the console)

   /op @p

4. Place a fence in the spawn protection and leash a mob to it

5. Switch to Survival mode

   /gamemode survival @p

6. De-op yourself

   /deop @p

7. Left click the leash knot
   ✔ You cannot destroy it as expected

8. Right click the leash knot
   ❌ It breaks