Fix signed book page serialization (#10696)

patches/server/1042-General-ItemMeta-fixes.patch

@@ -156,7 +156,7 @@ index 12911233c01d0ac1af9adbd157d56d28361fc76f..99ee41e79891d6017f065492efab5af9
  
      private static Material shieldToBannerHack() {
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBookSigned.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBookSigned.java
-index 3f78a0935d738854182254b345064e3c225dcd5f..1d63632372eb8b078bbbba6f9e583eb93c902746 100644
+index 3f78a0935d738854182254b345064e3c225dcd5f..218df87c596d47b431dbbf2aa42822ef174f948f 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBookSigned.java
 +++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaBookSigned.java
 @@ -116,8 +116,8 @@ public class CraftMetaBookSigned extends CraftMetaItem implements BookMeta {
@@ -179,6 +179,21 @@ index 3f78a0935d738854182254b345064e3c225dcd5f..1d63632372eb8b078bbbba6f9e583eb9
          }
      }
  
+@@ -358,7 +358,13 @@ public class CraftMetaBookSigned extends CraftMetaItem implements BookMeta {
+         }
+ 
+         if (this.pages != null) {
+-            builder.put(CraftMetaBookSigned.BOOK_PAGES.BUKKIT, ImmutableList.copyOf(this.pages));
++            // Paper start - deserialization expects json
++            final List<String> jsonPages = new ArrayList<>(this.pages.size());
++            for (final Component page : this.pages) {
++                jsonPages.add(CraftChatMessage.toJSON(page));
++            }
++            builder.put(CraftMetaBookSigned.BOOK_PAGES.BUKKIT, ImmutableList.copyOf(jsonPages));
++            // Paper end - deserialization expects json
+         }
+ 
+         if (this.resolved) {
 diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java
 index 8e0dd4b7a7a25a8beb27b507047bc48d8227627c..cf5d27ccc2225bac3aa57912f444f95d2f37e32e 100644
 --- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java