kivy: settings dialog: call update() from __init__

this is a clearer/easier-to-understand API

electrum/gui/kivy/main_window.py

@@ -723,7 +723,8 @@ class ElectrumWindow(App, Logger):
         from .uix.dialogs.settings import SettingsDialog
         if self._settings_dialog is None:
             self._settings_dialog = SettingsDialog(self)
-        self._settings_dialog.update()
+        else:
+            self._settings_dialog.update()
         self._settings_dialog.open()
 
     def lightning_open_channel_dialog(self):
@@ -1183,7 +1184,8 @@ class ElectrumWindow(App, Logger):
         from .uix.dialogs.addresses import AddressesDialog
         if self._addresses_dialog is None:
             self._addresses_dialog = AddressesDialog(self)
-        self._addresses_dialog.update()
+        else:
+            self._addresses_dialog.update()
         self._addresses_dialog.open()
 
     def fee_dialog(self):

electrum/gui/kivy/uix/dialogs/addresses.py

@@ -237,6 +237,7 @@ class AddressesDialog(Factory.Popup):
     def __init__(self, app: 'ElectrumWindow'):
         Factory.Popup.__init__(self)
         self.app = app
+        self.update()
 
     def get_card(self, addr, balance, is_used, label):
         ci = {}

electrum/gui/kivy/uix/dialogs/settings.py

@@ -122,6 +122,8 @@ class SettingsDialog(Factory.Popup):
         self._unit_dialog = None
         self._coinselect_dialog = None
 
+        self.update()
+
     def update(self):
         self.wallet = self.app.wallet
         self.use_encryption = self.wallet.has_password() if self.wallet else False