wallet: fire fewer 'status' and 'wallet_updated' triggers

Especially during initial history sync, there are a lot of False->False up_to_date transitions
(e.g. adb.add_address generates one), and the GUI does some work for each, which adds up to a lot
of CPU usage for the full sync.

electrum/wallet.py

@@ -465,6 +465,7 @@ class Abstract_Wallet(ABC, Logger, EventListener):
             self.adb.reset_netrequest_counters()  # sync progress indicator
             self.save_db()
         # fire triggers
+        if status_changed or up_to_date:  # suppress False->False transition, as it is spammy
             util.trigger_callback('wallet_updated', self)
             util.trigger_callback('status')
         if status_changed: