Fix NPE and NoSuchElementException in Towny integration

[adabugra]

Fixess NPE when handling offline player at TownAddResidentEvent. Fixes NoSuchElementException that occurs when attempting to modify roles for users not in the cache at TownMayorChangeEvent. Stacktrace:

[18:29:50] [Server thread/ERROR]: Could not pass event TownMayorChangeEvent to Farmer vv6-b108
java.util.NoSuchElementException: No value present
	at java.base/java.util.Optional.get(Optional.java:143) ~[?:?]
	at Farmer-v6-b108.jar/xyz.geik.farmer.api.managers.FarmerManager.changeOwner(FarmerManager.java:71) ~[Farmer-v6-b108.jar:?]
	at Farmer-v6-b108.jar/xyz.geik.farmer.integrations.townyadvanced.TownyListener.transferTown(TownyListener.java:68) ~[Farmer-v6-b108.jar:?]
	at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor1116.execute(Unknown Source) ~[?:?]
	at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:77) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
	at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
	at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:71) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.callEvent(PaperPluginManagerImpl.java:131) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:629) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
	at Towny-0.100.4.0.jar/com.palmergames.bukkit.util.BukkitTools.fireEvent(BukkitTools.java:373) ~[Towny-0.100.4.0.jar:?]
	at Towny-0.100.4.0.jar/com.palmergames.bukkit.util.BukkitTools.isEventCancelled(BukkitTools.java:354) ~[Towny-0.100.4.0.jar:?]
	at Towny-0.100.4.0.jar/com.palmergames.bukkit.towny.command.TownCommand.lambda$townSetMayor$10(TownCommand.java:1998) ~[Towny-0.100.4.0.jar:?]
	at Towny-0.100.4.0.jar/com.palmergames.bukkit.towny.scheduling.TaskScheduler.lambda$run$1(TaskScheduler.java:82) ~[Towny-0.100.4.0.jar:?]
	at Towny-0.100.4.0.jar/com.palmergames.bukkit.towny.scheduling.impl.FoliaTaskScheduler.lambda$run$0(FoliaTaskScheduler.java:59) ~[Towny-0.100.4.0.jar:?]
	at io.papermc.paper.threadedregions.scheduler.FoliaEntityScheduler$EntityScheduledTask.accept(FoliaEntityScheduler.java:168) ~[leaf-1.21.1.jar:?]
	at io.papermc.paper.threadedregions.scheduler.FoliaEntityScheduler$EntityScheduledTask.accept(FoliaEntityScheduler.java:115) ~[leaf-1.21.1.jar:?]
	at io.papermc.paper.threadedregions.EntityScheduler.executeTick(EntityScheduler.java:185) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1767) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:521) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1638) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1325) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319) ~[leaf-1.21.1.jar:1.21.1-DEV-0927bfb]
	at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]