Drop manual isEditable copy in CraftSign

Signs no longer have a specific isEdiable state, the entire API in this
regard needs updating/deprecation. The boolean field is completely gone,
replaced by a uuid (which will need a new setEditingPlayer(UUID) method
on the Sign interface), and the current upstream implementation of
setEdiable simply flips the is_waxed state.

This patch is hence not needed as it neither allows editing (which will
be redone in a later patch) nor is required to copy the is_waxed boolean
flag as it lives in the signs compound tag and is covered by applyTo.

patches/server/0748-Add-API-for-item-entity-health.patch

@@ -1,34 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Jake Potrebic <jake.m.potrebic@gmail.com>
-Date: Sat, 28 Aug 2021 09:00:45 -0700
-Subject: [PATCH] Add API for item entity health
-
-== AT ==
-public net.minecraft.world.entity.item.ItemEntity health
-
-diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
-index 27e961653dc66fbe8d5421eef04260b91ca410f4..e9946edf568db010e4ccb9fe7755709ed7b8310f 100644
---- a/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
-+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftItem.java
-@@ -102,6 +102,21 @@ public class CraftItem extends CraftEntity implements Item {
-      public void setWillAge(boolean willAge) {
-         item.age = willAge ? 0 : NO_AGE_TIME;
-      }
-+
-+    @Override
-+    public int getHealth() {
-+        return item.health;
-+    }
-+
-+    @Override
-+    public void setHealth(int health) {
-+        if (health <= 0) {
-+            item.getItem().onDestroyed(item);
-+            item.discard();
-+        } else {
-+            item.health = health;
-+        }
-+    }
-     // Paper End
- 
-     @Override