In "creationView" I can't use two fields of type "reference" related to the same entity.

In "creationView" I can't use two fields of type "reference" related to the same entity.
If I use two fields the data is duplicated in the select input, if I used three fields the data are tripled, and so on.

Entity Wallet:

```
"wallets": [{
"id": 1,
"currency": "ZZ",
"owner": 1,
"balance": "123123",
"country": "ASD",
"modification": "2015-10-13T15:20:43.366371Z",
"creation": "2015-10-13T15:20:43.366371Z"
}]

"charges": [{
...
"source_wallet": 5
"beneficiary_wallet": 8
...
}]
```

The Create View

```
charges.creationView()
.title('Create new Charge')
.fields([
...
nga.field('source_wallet', 'reference')
.label('Source Wallet')
.targetEntity(admin.getEntity('wallets'))
.targetField(nga.field('id'))
.singleApiCall(ids => ({ 'id': ids })),
nga.field('beneficiary_wallet', 'reference')
.label('Beneficiary Wallet')
.targetEntity(admin.getEntity('wallets'))
.targetField(nga.field('id'))
.singleApiCall(ids => ({ 'id': ids })),
...
]);
```

Start with the charges.creationView() configuration and the two reference fields shown in the report, using the wallets and charges data to reproduce the duplicated select options. Trace how multiple reference fields targeting the same wallets entity load their choices; done means each field displays the wallets once rather than duplicating them.

Written by the indexing model from the issue text.