Dashboard checks for updates despite disabling update check

This may not be fully fixed – I have installed TrueNAS 12.0-BETA in an isolated network for evaluation, and even after disabling the check for updates I'm seeing the following in the logs:

[2020/07/29 15:18:34] (DEBUG) urllib3.connectionpool._new_conn():955 - Starting new HTTPS connection (1): update-master.ixsystems.com:443
[2020/07/29 15:18:44] (ERROR) freenasOS.Configuration.TryGetNetworkFile():692 - Unable to connect to url https://update-master.ixsystems.com/TrueNAS/trains.txt: HTTPSConnectionPool(host='update-master.ixsystems.com', port=443): Max retries exceeded with url: /TrueNAS/trains.txt (Caused by ConnectTimeoutError(<urllib3.connection.VerifiedHTTPSConnection object at 0x81e89af70>, 'Connection to update-master.ixsystems.com timed out. (connect timeout=10)'))
[2020/07/29 15:18:44] (ERROR) freenasOS.Configuration.TryGetNetworkFile():709 - Unable to load ['https://update.ixsystems.com/TrueNAS/trains.txt', 'https://update-master.ixsystems.com/TrueNAS/trains.txt']: Unable to connect to url https://update-master.ixsystems.com/TrueNAS/trains.txt
[2020/07/29 15:18:44] (WARNING) application.call_method():173 - Exception while calling update.check_available(*[])
Traceback (most recent call last):
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 137, in call_method}}
{{ result = await self.middleware._call(message['method'], serviceobj, methodobj, params, app=self,}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1198, in _call}}
{{ return await self.run_in_executor(prepared_call.executor, methodobj, *prepared_call.args)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1102, in run_in_executor}}
{{ return await loop.run_in_executor(pool, functools.partial(method, *args, **kwargs))}}
{{ File "/usr/local/lib/python3.8/concurrent/futures/thread.py", line 57, in run}}
{{ result = self.fn(*self.args, **self.kwargs)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 977, in nf}}
{{ return f(*args, **kwargs)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/plugins/update.py", line 240, in check_available}}
{{ trains = self.middleware.call_sync('update.get_trains')}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1253, in call_sync}}
{{ return self.run_coroutine(self.run_in_executor(prepared_call.executor, methodobj, *prepared_call.args))}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1285, in run_coroutine}}
{{ return fut.result()}}
{{ File "/usr/local/lib/python3.8/concurrent/futures/_base.py", line 432, in result}}
{{ return self.__get_result()}}
{{ File "/usr/local/lib/python3.8/concurrent/futures/_base.py", line 388, in __get_result}}
{{ raise self._exception}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1102, in run_in_executor}}
{{ return await loop.run_in_executor(pool, functools.partial(method, *args, **kwargs))}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/utils/io_thread_pool_executor.py", line 25, in run}}
{{ result = self.fn(*self.args, **self.kwargs)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/schema.py", line 977, in nf}}
{{ return f(*args, **kwargs)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/plugins/update.py", line 119, in get_trains}}
{{ trains_data = self.middleware.call_sync('update.get_trains_data')}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/main.py", line 1256, in call_sync}}
{{ return methodobj(*prepared_call.args)}}
{{ File "/usr/local/lib/python3.8/site-packages/middlewared/plugins/update_/trains_freebsd.py", line 109, in get_trains_data}}
{{ for name, descr in (conf.AvailableTrains() or {}).items():}}
{{ File "/usr/local/lib/freenasOS/Configuration.py", line 987, in AvailableTrains}}
{{ fileref = self.TryGetNetworkFile(file=TRAIN_FILE, reason="FetchTrains")}}
{{ File "/usr/local/lib/freenasOS/Configuration.py", line 710, in TryGetNetworkFile}}
{{ raise url_exc}}
freenasOS.Exceptions.UpdateNetworkConnectionException: Unable to connect to url https://update-master.ixsystems.com/TrueNAS/trains.txt

11.3 PR: https://github.com/freenas/webui/pull/4101

12.0 PR: https://github.com/freenas/webui/pull/4100