Fenix Chronos software version 15.81 Beta

Changes made from version 15.51 to 15.81:

Fixed an issue where one couldn't Race an activity from the activity history menu.
Fixed an issue where some devices were reporting a higher than expected battery drain.
Fixed an intermittent issue where the device could crash during an activity.
Fixed an issue where the GPS updates were failing to install.
Fixed an issue where the data screen background color would remain inverted, if ending a swim workout early.