Service apartment in a residential apartment

Sevice apartments too are residential. There are no legal or rational grounds for opposing such an arrangement.

Service apartment are not commercial place, it is another residential tenements, so the association has no reason to object.

You may go ahead with your proposal, if the association objects then you may question their authority to object or ask them to quote the relevant law or rule in this regard.

If they still insist then you may issue a legal notice to contain them.