Fixed command exploit with C12

patches/minecraft/net/minecraft/network/NetHandlerPlayServer.java.patch

@@ -152,3 +152,15 @@
                  }
  
                  break;
+@@ -1080,7 +1110,10 @@
+                 return;
+             }
+ 
+-            System.arraycopy(p_147343_1_.func_180768_b(), 0, tileentitysign.field_145915_a, 0, 4);
++            IChatComponent[] lines = p_147343_1_.func_180768_b(); //Forge: Prevent client from directly sending commands
++            for (int x = 0; x < tileentitysign.field_145915_a.length && x < lines.length; x++)
++                tileentitysign.field_145915_a[x] = new ChatComponentText(lines[x].func_150260_c());
++
+             tileentitysign.func_70296_d();
+             worldserver.func_175689_h(blockpos);
+         }