Returns true if the active provider and device support energy-usage tracking, otherwise returns false.
On some platforms whether the device actually exposes usable energy monitors is resolved
asynchronously after IEnergyUsageControl.StartEnergyUsageTracking is called, so this property can start
out true and later become false (for example, when the device turns out to have no
usable power monitors). Re-check it after starting rather than only once up front, and treat a
transition to false as tracking no longer being available.