I'm not certain of a policy. Right now the contract you're looking at is for a specific period of time, and the intent would be to use the information for the purposes for which it's collected, for that period of time. I believe there are options for several additional years, and there is research internationally about the use of mobility data to support public health.
I believe there are uses beyond COVID, but the agency has not taken any decision to use it beyond the COVID pandemic at this time.