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/0785-Fix-Entity-Position-Desync.patch

@@ -1,23 +0,0 @@
-From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
-From: Owen1212055 <23108066+Owen1212055@users.noreply.github.com>
-Date: Thu, 23 Dec 2021 23:59:12 -0500
-Subject: [PATCH] Fix Entity Position Desync
-
-If entities were teleported in the first tick it would not be send to the client.
-
-This excludes hanging entities, as this fix caused problematic behavior due to them having their own
-position field.
-
-diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
-index 63561c0044375465fa0023b2b563a6516d7fa76c..6670e657e08e130f7e0368f418379fd1ece00cdf 100644
---- a/src/main/java/net/minecraft/server/level/ServerEntity.java
-+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
-@@ -174,7 +174,7 @@ public class ServerEntity {
-                 boolean flag4 = false;
-                 boolean flag5 = false;
- 
--                if (this.tickCount > 0 || this.entity instanceof AbstractArrow) {
-+                if (!(this.entity instanceof net.minecraft.world.entity.decoration.HangingEntity) || this.tickCount > 0 || this.entity instanceof AbstractArrow) { // Paper - Always update position
-                     long k = this.positionCodec.encodeX(vec3d);
-                     long l = this.positionCodec.encodeY(vec3d);
-                     long i1 = this.positionCodec.encodeZ(vec3d);