ONE_TO_MANY with cutom join columns should not require ID

[erik-sab]

Issue description

With structure like:

@MappedEntity("foo")
public record Foo(
    @Id String id,
    @Nullable
        @Relation(Relation.Kind.ONE_TO_MANY)
        @JoinColumns({
          @JoinColumn(name = ID_COL, referencedColumnName = "foo_id")
        })
        List<Bar> bars,

@MappedEntity("bar")
public record Bar(
    @NonNull String anotherReferenceId,
    @NonNull String yetAnotherReferenceId,
    @NonNull String fooId,

The goal is to list Bar instances by fooId.

When trying to use this structure, it fails compilation with an error:

Unable to implement Repository method: FooRepository.getById(String id). Associated entity [Bar] defines no ID. Cannot join.

However join column is explicitly specified, therefore it should not be required.

Workaround: Create composite ID from all 3 reference fields in Bar - then join works as expected.