Dry Firing the Shield to release the striker won't hurt it. Neither will leaving the striker set (cocked) for indefinite periods of time.
When doing club matches, after the timer is stopped, we always end with the RO inspecting the weapon to ensure that the gun is empty, point it down range, dry fire it and holster it, before leaving the 'stage'.
I've gotten into the habit of doing this with any pistol I'm not carrying, at the end of every range session. My Wife, OTOH, has the habit of leaving every pistol (that she's not carrying) with the slide locked open when she puts them in her bag, ensuring that there is not a round in the gun. Neither way will mess up the springs of a Shield, or other Striker Fired pistol.