NullPointerException when using southern facing cruise sign

[TrollyLoki]

Describe the bug Whenever I attempt to enable crusing while facing south there is a NullPointerException in my console:

[16:07:17] [Server thread/ERROR]: Could not pass event PlayerInteractEvent to Movecraft v7.0.0.1_for_1.8.8-1.16.2
java.lang.NullPointerException: null
	at org.bukkit.material.Sign.getFacing(Sign.java:134) ~[patched_1.16.5.jar:git-Paper-503]
	at net.countercraft.movecraft.sign.CruiseSign.onSignClick(CruiseSign.java:70) ~[?:?]
	at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor87.execute(Unknown Source) ~[?:?]
	at org.bukkit.plugin.EventExecutor.lambda$create$1(EventExecutor.java:69) ~[patched_1.16.5.jar:git-Paper-503]
	at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[patched_1.16.5.jar:git-Paper-503]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[patched_1.16.5.jar:git-Paper-503]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:607) ~[patched_1.16.5.jar:git-Paper-503]
	at org.bukkit.craftbukkit.v1_16_R3.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:528) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.PlayerInteractManager.a(PlayerInteractManager.java:464) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.PlayerConnection.a(PlayerConnection.java:1553) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.PacketPlayInUseItem.a(PacketPlayInUseItem.java:27) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.PacketPlayInUseItem.a(PacketPlayInUseItem.java:5) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.PlayerConnectionUtils.lambda$ensureMainThread$1(PlayerConnectionUtils.java:23) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.TickTask.run(SourceFile:18) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.MinecraftServer.bb(MinecraftServer.java:1138) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.MinecraftServer.executeNext(MinecraftServer.java:1131) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.IAsyncTaskHandler.executeAll(IAsyncTaskHandler.java:95) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.MinecraftServer.a(MinecraftServer.java:1267) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.MinecraftServer.w(MinecraftServer.java:1002) ~[patched_1.16.5.jar:git-Paper-503]
	at net.minecraft.server.v1_16_R3.MinecraftServer.lambda$a$0(MinecraftServer.java:175) ~[patched_1.16.5.jar:git-Paper-503]
	at java.lang.Thread.run(Unknown Source) [?:1.8.0_281]

To Reproduce Steps to reproduce the behavior:

1. Create a craft
2. Place a cruise sign facing south
3. Pilot the craft and right click on the cruise sign
4. Nothing happens in-game and the error appears on the console (sign text is still updated)

Expected behavior The craft should start crusing south like any other direction

Versions (please complete the following information):

• Movecraft: 7.0.0.1
• Java: JRE 1.8.0_281
• Minecraft: 1.16.5 (git-Paper-503)