In an action to enforce subdivision (a) of Section 14052, the court shall allow the prevailing plaintiff other than the state or political subdivision of the state, a reasonable attorney’s fee consistent with the standards established in Serrano v. Priest (1977) 20 Cal.3d 25, 48-49, and litigation expenses including, but not limited to, expert witness fees and expenses as part of the costs. A prevailing defendant shall not recover any costs, unless the court finds the action to be frivolous, unreasonable, or without foundation.