Some of Bianca's dialogue suggests she'll be around for a while, but it's never been announced as anything other than a "short stint", so I'm not sure what that means. I'd assume she'll be around now to facilitate Whitney's exit (which cannot come soon enough because it does feel like the writers are throwing the character under the bus, somewhat, with all the Britney stuff).
I do wonder whether Letitia Dean's unplanned absence meant Lorraine Stanley's previous return was cut short, and she's coming back now to play out bits of the plot she wasn't able to beforehand.