BUGFIX: Do not join select property paths to embedded objects
BUGFIX: Do not join select property paths to embedded objects

Instead of assuming that every property path with a dot is a path
to an other entity check if the property path is a mapped field which
is also true for embedded object properties.

Resolves #989

neos/flow-development-collection,bwaidelich/flow-development-collection,neos/flow-development-collection,dlubitz/flow-development-collection,fcool/flow-development-collection,neos/flow-development-collection,fcool/flow-development-collection,daniellienert/flow-development-collection,fcool/flow-development-collection,kdambekalns/flow-development-collection,kdambekalns/flow-development-collection,albe/flow-development-collection,robertlemke/flow-development-collection,albe/flow-development-collection,kdambekalns/flow-development-collection,daniellienert/flow-development-collection,robertlemke/flow-development-collection,kdambekalns/flow-development-collection,neos/flow-development-collection,dlubitz/flow-development-collection,robertlemke/flow-development-collection,bwaidelich/flow-development-collection,albe/flow-development-collection,fcool/flow-development-collection,robertlemke/flow-development-collection,bwaidelich/flow-development-collection,dlubitz/flow-development-collection,daniellienert/flow-development-collection