Add back logging for added coins (#2720)

It was removed in commit ee3dfb9 for
unknown reason. A few people on keybase have learned to rely on it to
check for new coins being received by their wallet. Arguably not the
best way to do so but seems like a useful log output to have in general.

chia/wallet/wallet_state_manager.py

@@ -655,6 +655,7 @@ async def coin_added(
         """
         Adding coin to DB
         """
+        self.log.info(f"Adding coin: {coin} at {height}")
         farm_reward = False
         if coinbase or fee_reward:
             farm_reward = True