fix(doctrine): filter parent link from uri variables in fetch_data=false reference

[soyuka]

Summary

IriConverter::getResourceFromIri($iri, ['fetch_data' => false]) on a subresource IRI (e.g. /companies/{companyId}/employees/{id}) threw Doctrine\ORM\Exception\UnrecognizedIdentifierFields because the ORM ItemProvider passed the entire $uriVariables array — including the parent link companyId — to EntityManager::getReference(). Doctrine rejects any key that is not an own identifier of the entity.

The provider now reads the entity's own identifier field names, intersects them with $uriVariables, and only short-circuits to getReference() when every own identifier is present (passing just those keys); otherwise it falls through to the normal query that resolves the link. This mirrors the existing ODM ItemProvider behaviour and correctly handles composite identifiers. Also removes the stale // todo that flagged this exact fragility.

Reproduction

Following the docs Company/Employee subresource example, resolving an Employee IRI with fetch_data: false raised UnrecognizedIdentifierFields ('companyId') instead of returning a reference. Also affected SearchFilter when an IRI is passed.

Test plan

• Added failing test covering the bug (testGetItemWithFetchDataFalseOnSubresourceFiltersParentLink).
• Test passes after the fix (getReference called with ['id' => 2], not the parent link).
• ORM State suite, IriConverterTest, and functional subresource suites pass locally.

Fixes #8124