build: fix mongodb port for tests (#7132)
build: fix mongodb port for tests (#7132)

to avoid conflicting with dev instance

fixes: #7127
openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server,openfoodfacts/openfoodfacts-server