What are the legitimate channels for a sum of money acquired from usurious interest on a apartment insurance deposit, such as donating it to a mosque or giving it to a poor Muslim or non-Muslim?

If the amount paid is a pledge, then its growth is a right of the pledger (the tenant). If the growth comes from a permissible source, then it is lawful to benefit from it. However, if it comes from forbidden transactions, such as depositing it in an interest-based bank—as seems to be the case from the question—then it is obligatory to dispose of it by spending it on charitable causes for Muslims, such as mosques or their poor. It is prohibited to leave the interest for the interest-based bank.