ConcurrentModificationException during testExecutionAndCancellationWithToken()

[DivineThreepwood]

The following issue was discovered by the ci tests:

testExecutionAndCancellationWithToken()
java.util.ConcurrentModificationException
	at java.base/java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1013)
	at java.base/java.util.ArrayList$Itr.next(ArrayList.java:967)
	at org.openbase.bco.dal.remote.action.RemoteAction.isDone(RemoteAction.java:648)
	at java.base/java.util.ArrayList.removeIf(ArrayList.java:1672)
	at java.base/java.util.ArrayList.removeIf(ArrayList.java:1660)
	at java.base/java.util.Collections$SynchronizedCollection.removeIf(Collections.java:2135)
	at org.openbase.bco.dal.test.AbstractBCOTest.observe(AbstractBCOTest.java:379)
	at org.openbase.bco.dal.test.AbstractBCOTest.observe(AbstractBCOTest.java:362)
	at org.openbase.bco.dal.test.AbstractBCOTest.waitForExecution(AbstractBCOTest.java:148)
	at org.openbase.bco.dal.test.action.RemoteActionTest.testExecutionAndCancellationWithToken(RemoteActionTest.kt:108)