Shop does not work with custom model data vehicles

[stijnb1234]

Describe the bug
Shop does not work with custom model data vehicles

To Reproduce
Steps to reproduce the behavior:

1. Create vehicle with custom model data
2. Run /vp shop
3. See error

Expected behavior
Should just open.

Screenshots or Video Recordings

[20:55:04] [Server thread/WARN]: [VehiclesPlusPro] Task #37780 for VehiclesPlusPro v2.4 generated an exception
java.lang.ClassCastException: class org.bukkit.craftbukkit.v1_16_R3.inventory.CraftMetaItem cannot be cast to class org.bukkit.inventory.meta.LeatherArmorMeta (org.bukkit.craftbukkit.v1_16_R3.inventory.CraftMetaItem and org.bukkit.inventory.meta.LeatherArmorMeta are in unnamed module of loader 'app')
    at me.legofreak107.vehiclesplus.gui.vehicles.VehicleShopGUI$1$1.run(VehicleShopGUI.java:87) ~[?:?]
    at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftTask.run(CraftTask.java:100) ~[patched_1.16.5.jar:git-Purpur-1171]
    at org.bukkit.craftbukkit.v1_16_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:468) ~[patched_1.16.5.jar:git-Purpur-1171]
    at net.minecraft.server.v1_16_R3.MinecraftServer.b(MinecraftServer.java:1503) ~[patched_1.16.5.jar:git-Purpur-1171]
    at net.minecraft.server.v1_16_R3.DedicatedServer.b(DedicatedServer.java:449) ~[patched_1.16.5.jar:git-Purpur-1171]
    at net.minecraft.server.v1_16_R3.MinecraftServer.a(MinecraftServer.java:1416) ~[patched_1.16.5.jar:git-Purpur-1171]
    at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1142) ~[patched_1.16.5.jar:git-Purpur-1171]
    at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:293) ~[patched_1.16.5.jar:git-Purpur-1171]

Server and Plugin Information

• Installed plugins: N/a
• VehiclesPlus Version: 2.4
• Server Platform and Version [eg: PaperSpigot 1.x.x #xxx]: Spigot 1.16.5
• Operating System (if applicable): N/a

[stijnb1234]

Fixed in v2.4.1