Unclear error message upon non-existing incarnation when reloading effects

[DanySK]

If an incarnation is no longer available when an effect is requested, an unclear error is printed:

> Task :00-minimal
10:03:42.200 [main] WARN  it.unibo.alchemist.Alchemist - Available launchers: [Alchemist headless runner, Alchemist Swing graphical simulation]
10:03:42.204 [main] WARN  it.unibo.alchemist.launch.Launcher - Alchemist Swing graphical simulation selected because Graphical effects requested, priority shifts up
10:03:43.152 [main] WARN  i.u.a.loader.m2m.SimulationModel - No seeds specified, defaulting to 0 for both scenario and simulation
10:03:43.165 [main] WARN  i.u.a.loader.m2m.SimulationModel - No environment specified, defaulting to Continuous2DEnvironment
10:03:43.185 [main] WARN  i.u.a.loader.m2m.SimulationModel - There are no displacements in the specification, the environment won't have any node
Exception in thread "main" java.util.NoSuchElementException
        at org.danilopianini.lang.ImmutableCollectionWithCurrentElement.setCurrent(ImmutableCollectionWithCurrentElement.java:111)
        at org.danilopianini.lang.ImmutableCollectionWithCurrentElement.<init>(ImmutableCollectionWithCurrentElement.java:33)
        at it.unibo.alchemist.boundary.gui.effects.EffectSerializationFactory$2.read(EffectSerializationFactory.java:63)
        at it.unibo.alchemist.boundary.gui.effects.EffectSerializationFactory$2.read(EffectSerializationFactory.java:54)
        at com.google.gson.internal.bind.TypeAdapters$35$1.read(TypeAdapters.java:894)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:131)
        at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:222)
        at com.google.gson.TypeAdapter.fromJsonTree(TypeAdapter.java:285)
        at com.google.gson.typeadapters.RuntimeTypeAdapterFactory$1.read(RuntimeTypeAdapterFactory.java:231)
        at com.google.gson.TypeAdapter$1.read(TypeAdapter.java:199)
        at com.google.gson.internal.bind.TypeAdapterRuntimeTypeWrapper.read(TypeAdapterRuntimeTypeWrapper.java:41)
        at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:82)
        at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61)
        at com.google.gson.Gson.fromJson(Gson.java:932)
        at com.google.gson.Gson.fromJson(Gson.java:897)
        at it.unibo.alchemist.boundary.gui.effects.EffectSerializationFactory.effectsFromFile(EffectSerializationFactory.java:112)
        at it.unibo.alchemist.boundary.gui.SingleRunGUI.make(SingleRunGUI.java:157)
        at it.unibo.alchemist.boundary.gui.SingleRunGUI.make(SingleRunGUI.java:111)
        at it.unibo.alchemist.launch.SingleRunSwingUI.launch(SingleRunSwingUI.kt:46)
        at it.unibo.alchemist.launch.SimulationLauncher.launch(SimulationLauncher.kt:52)
        at it.unibo.alchemist.launch.Launcher.invoke(Launcher.kt:44)
        at it.unibo.alchemist.Alchemist.launch(Alchemist.kt:170)
        at it.unibo.alchemist.Alchemist.main(Alchemist.kt:128)

Reproducible at https://github.com/AlchemistSimulator/SAPERE-incarnation-tutorial/tree/5ee7ead4d51cd3acb3e0863cd3bc49a36bd07953, with ./gradlew 00