DataGrid aggregation doesn't work with composite entities

[KremnevDmitry]

Environment

Jmix version: 2.2.999-SNAPSHOT

Bug Description

Let's assume that two entities are defined: Order and OrderLineItem with a one-to-many @composition.
The OrderDetailView contains a DataGrid of OrderLineItem.

If you enable aggregation for this DatGrid and add multiple items, an error will occur.

Current Behavior

An error:

java.lang.IllegalArgumentException: entity or id is null
	at io.jmix.core.common.util.Preconditions.checkNotNullArgument(Preconditions.java:101)
	at io.jmix.flowui.model.impl.CollectionContainerImpl.getItemIndex(CollectionContainerImpl.java:123)
	at io.jmix.flowui.model.impl.CollectionContainerImpl.getItemOrNull(CollectionContainerImpl.java:117)
	at io.jmix.flowui.model.impl.CollectionContainerImpl.getItem(CollectionContainerImpl.java:108)
	at io.jmix.flowui.data.grid.ContainerDataGridItems.getItemValue(ContainerDataGridItems.java:208)
	at io.jmix.flowui.data.aggregation.impl.AggregatableDelegate.lambda$valuesByProperty$0(AggregatableDelegate.java:197)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.AbstractList$RandomAccessSpliterator.forEachRemaining(AbstractList.java:720)

Expected Behavior

Aggregation will be updated without any errors.

Sample Project

aggregationBug.zip

[KremnevDmitry]

UPD:

The error occurred because the io.jmix.core.entity.EntityValues#getId method was used as aggregation items ID provider.

Since composite entities receive their ID only after the parent entity is saved, this method of getting the ID would throw an error. Now io.jmix.core.entity.EntityValues#getIdOrEntity will be used.