asyncio: addr_sync: maybe fix "no current event loop in thread"
asyncio: addr_sync: maybe fix "no current event loop in thread"

see https://github.com/spesmilo/electrum/issues/5376
crash report for electrum 4.2.1:
```
Traceback (most recent call last):
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/base.py", line 347, in mainloop
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/base.py", line 391, in idle
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/base.py", line 342, in dispatch_input
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/base.py", line 308, in post_dispatch_input
  File "kivy/_event.pyx", line 724, in kivy._event.EventDispatcher.dispatch
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/uix/behaviors/button.py", line 179, in on_touch_up
  File "kivy/_event.pyx", line 720, in kivy._event.EventDispatcher.dispatch
  File "kivy/_event.pyx", line 1263, in kivy._event.EventObservers.dispatch
  File "kivy/_event.pyx", line 1147, in kivy._event.EventObservers._dispatch
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/python-installs/Electrum/kivy/lang/builder.py", line 57, in custom_callback
  File "<string>", line 42, in <module>
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/gui/kivy/uix/dialogs/wallets.py", line 70, in cb
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/gui/kivy/main_window.py", line 710, in load_wallet_by_name
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/gui/kivy/main_window.py", line 728, in on_open_wallet
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/gui/kivy/main_window.py", line 691, in on_wizard_success
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/wallet.py", line 3267, in __new__
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/wallet.py", line 3111, in __init__
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/wallet.py", line 2904, in __init__
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/wallet.py", line 288, in __init__
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/address_synchronizer.py", line 97, in __init__
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/wallet.py", line 402, in load_and_cleanup
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/address_synchronizer.py", line 106, in load_and_cleanup
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/util.py", line 439, in <lambda>
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/util.py", line 435, in do_profile
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/address_synchronizer.py", line 432, in load_local_history
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/address_synchronizer.py", line 533, in _add_tx_to_local_history
  File "/home/user/wspace/electrum/.buildozer/android/app/electrum/address_synchronizer.py", line 548, in _mark_address_history_changed
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/other_builds/python3/arm64-v8a__ndk_target_21/python3/Lib/asyncio/locks.py", line 260, in __init__
  File "/home/user/wspace/electrum/.buildozer/android/platform/build-arm64-v8a/build/other_builds/python3/arm64-v8a__ndk_target_21/python3/Lib/asyncio/events.py", line 639, in get_event_loop
RuntimeError: There is no current event loop in thread 'GUI'.
```

pooler/electrum-ltc,pooler/electrum-ltc,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc,spesmilo/electrum,spesmilo/electrum,pooler/electrum-ltc