It is not possible to change the time for Sensor auto reset.
You can however, achieve this through firmware by calling the CapSense_InitializeAllBaselines API if the sensor is active for a certain period.
You can use systick timer to measure the duration for which sensor is active and call the API when certain amount of time has elapsed.
Please refer this KBA for details on how to use systick timer to measure button press duration.
Thanks and regards