Fix autocomplete special price

[romainruaud]

This one fix #682

Main problem is due to the fact that "special_price" is not selected in autocomplete. I thought addPriceData() would do this, but it's not the case.

The only reason the same bug is not appearing on catalog listing is that special_price is set to used_in_product_listing=1 and get automatically loaded by the layer.

I did not want to load all attributes used_in_product_listing=1 in the autocomplete (for performances concern, however, this would have fixed the issue easily), so I added only 'special_price' to the list of default selected attributes.

I intentionally omitted to add "special_from_date" and "special_to_date".

This is due to the fact that they are used only with Magento CE and this could cause errors when these attributes are missing (if they were deleted, or when using Magento EE).

To allow proper handling of the special price when using these attributes, one will have to add them manually via DI like this :

    <type name="Smile\ElasticsuiteCatalog\Model\Autocomplete\Product\AttributeConfig">
        <arguments>
            <argument name="additionalSelectedAttributes" xsi:type="array">
                <item name="special_from_date" xsi:type="string">special_from_date</item>
                <item name="special_to_date" xsi:type="string">special_to_date</item>
            </argument>
        </arguments>
    </type>

Let me know if this solution is acceptable for you, or if we should do it another way ?

[afoucret]

@romainruaud Can you please append date to the PR and test it against Magento EE.

BR,

[romainruaud]

PR Update :

• I added date fields.

Tested working OK with EE version.