remove JD power extension (#6322)

Co-authored-by: Abhijith Chatra <[email protected]>

Author: thomasjball

targetconfig.json

@@ -350,7 +350,6 @@
             "microsoft/pxt-jacdac/motor": {},
             "microsoft/pxt-jacdac/multitouch": {},
             "microsoft/pxt-jacdac/potentiometer": {},
-            "microsoft/pxt-jacdac/power": {},
             "microsoft/pxt-jacdac/pulse-oximeter": {},
             "microsoft/pxt-jacdac/rain-gauge": {},
             "microsoft/pxt-jacdac/real-time-clock": {},
@@ -542,7 +541,6 @@
             "jacdac/pxt-jacdac/motor": {},
             "jacdac/pxt-jacdac/multitouch": {},
             "jacdac/pxt-jacdac/potentiometer": {},
-            "jacdac/pxt-jacdac/power": {},
             "jacdac/pxt-jacdac/pulse-oximeter": {},
             "jacdac/pxt-jacdac/rain-gauge": {},
             "jacdac/pxt-jacdac/real-time-clock": {},