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/0734-Prevent-ContainerOpenersCounter-openCount-from-going.patch

@@ -1,18 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Shane Freeder <theboyetronic@gmail.com>
-Date: Tue, 30 Nov 2021 05:30:35 +0000
-Subject: [PATCH] Prevent ContainerOpenersCounter openCount from going negative
-
-
-diff --git a/src/main/java/net/minecraft/world/level/block/entity/ContainerOpenersCounter.java b/src/main/java/net/minecraft/world/level/block/entity/ContainerOpenersCounter.java
-index ba06184bad7e8ae55cb2d55f6196e8f990d2811d..3e4b3eecc788c564f81b7929bfab7d2fdb6e307d 100644
---- a/src/main/java/net/minecraft/world/level/block/entity/ContainerOpenersCounter.java
-+++ b/src/main/java/net/minecraft/world/level/block/entity/ContainerOpenersCounter.java
-@@ -64,6 +64,7 @@ public abstract class ContainerOpenersCounter {
- 
-     public void decrementOpeners(Player player, Level world, BlockPos pos, BlockState state) {
-         int oldPower = Math.max(0, Math.min(15, this.openCount)); // CraftBukkit - Get power before new viewer is added
-+        if (this.openCount == 0) return; // Paper
-         int i = this.openCount--;
- 
-         // CraftBukkit start - Call redstone event