kivy: history screen: fix "future" txs

```
  3.96 | E | gui.kivy.uix.dialogs.crash_reporter.ExceptionHook | exception caught by crash reporter
Traceback (most recent call last):
  File "kivy/_clock.pyx", line 649, in kivy._clock.CyClockBase._process_events
  File "kivy/_clock.pyx", line 218, in kivy._clock.ClockEvent.tick
  File "/home/user/wspace/electrum/electrum/gui/kivy/main_window.py", line 1045, in update_wallet
    self.update_tabs()
  File "/home/user/wspace/electrum/electrum/util.py", line 462, in <lambda>
    return lambda *args, **kw_args: do_profile(args, kw_args)
  File "/home/user/wspace/electrum/electrum/util.py", line 458, in do_profile
    o = func(*args, **kw_args)
  File "/home/user/wspace/electrum/electrum/gui/kivy/main_window.py", line 506, in update_tabs
    self.update_tab(name)
  File "/home/user/wspace/electrum/electrum/gui/kivy/main_window.py", line 501, in update_tab
    s.update()
  File "/home/user/wspace/electrum/electrum/gui/kivy/uix/screens.py", line 161, in update
    history_card.data = [self.get_card(item) for item in history]
  File "/home/user/wspace/electrum/electrum/gui/kivy/uix/screens.py", line 161, in <listcomp>
    history_card.data = [self.get_card(item) for item in history]
  File "/home/user/wspace/electrum/electrum/gui/kivy/uix/screens.py", line 132, in get_card
    status, status_str = self.app.wallet.get_tx_status(tx_hash, tx_mined_info)
  File "/home/user/wspace/electrum/electrum/wallet.py", line 1491, in get_tx_status
    num_blocks_remainining = tx_mined_info.wanted_height - self.adb.get_local_height()
TypeError: unsupported operand type(s) for -: 'NoneType' and 'int'
```

electrum/gui/kivy/uix/screens.py

@@ -126,9 +126,12 @@ class HistoryScreen(CScreen):
             fee_text = '' if fee is None else 'fee: %d sat'%fee
         else:
             tx_hash = tx_item['txid']
-            tx_mined_info = TxMinedInfo(height=tx_item['height'],
-                                        conf=tx_item['confirmations'],
-                                        timestamp=tx_item['timestamp'])
+            tx_mined_info = TxMinedInfo(
+                height=tx_item['height'],
+                conf=tx_item['confirmations'],
+                timestamp=tx_item['timestamp'],
+                wanted_height=tx_item.get('wanted_height', None),
+            )
             status, status_str = self.app.wallet.get_tx_status(tx_hash, tx_mined_info)
             icon = f'atlas://{KIVY_GUI_PATH}/theming/atlas/light/' + TX_ICONS[status]
             message = tx_item['label'] or tx_hash