You must disclose the prepaid rent, and all other assets, under penalty of perjury. By deliberately failing to list an asset, you could end up being charged with bankruptcy fraud and being sent to federal prison.
List the prepaid rent as an asset. Check the Washington state exemption scheme to determine how best to exempt that asset from being seized. That is one of the key things that a bankruptcy lawyer should do for you.
The rule in bankruptcy is: DISCLOSE DISCLOSE DISCLOSE. That is how you stay out of trouble.