Can a compound with indirectly bonded carbon and silicon atoms within the same aromatic system be called organosilicon compound?
Organosilicon compounds fall under the broader category of Organometallic compounds. It is a requirement that in organometallic compounds, atleast one $\ce{C-M}$ bond should exist. Since Si is only bonded to oxygen atoms in your compound, the given compound is not an organosilicon compound.

The following is also mentioned in the wikipedia page for Organosilicon compounds, under the image:


  A carbon–silicon bond present in all organosilicon compounds