arrayPropItemTypeMap should be indexed with a specialKey

[arnedesmedt]

I don't know if this should be merged into master. If not, let me know.

The problem was that special key support was not working for arrayPropItemTypeMap.

In the toArray function of ImmutableRecordLogic the key of arrayPropItemTypeMap should be the propertyName (the one that is converted)
while in the fromArray function the key of arrayPropItemTypeMap should be the given key (the one that is not converted).

So I changed this that the converted key is also used in the fromArray function for arrayPropItemTypeMap.

I also tested this functionality in an existing test.

[arnedesmedt]

@codeliner or @sandrokeil any ideas on this one?

[codeliner]

@sandrokeil I think we can merge, or?

[codeliner]

ok, we checked it internally and it's indeed a bug that should be fixed. Good catch @arnedesmedt and thx for PR!

[arnedesmedt]

It's a pleasure! Thx for the great event-engine packages you made!