[-] PSCFV-11441 : filter on current shop ID for price index

Requirements :
- Multishop instance
- Shop with prices and products (and not the one with the id_shop 1)
- Blocklayered with prices slider enabled

Symptom :
- The prices slider is not shown

Analysis :
The blocklayered->getPriceFilterSubQuery() method doesn't not filter on the id_shop, so it retrieves the other shops price indexes (which are null if you have only products on other shops than the first one).
So, the results filtered by getPriceFilterSubQuery() contain min_price/max_price at 0 values => the slider is not shown on the front-office