When the user has already loaded a wallet in QML and tries to restore a
new wallet `WCHaveSeed.qml` incorrectly shows a `Finish` button instead
of a `Next` button and raises a KeyError if the user clicks on Finish
instead of resolving the passphrase input view (regression from
https://github.com/spesmilo/electrum/pull/10016).
This happens because `last` of `have_seed` depends on
`NewWalletWizard.is_single_password()` and NewWalletWizard.wants_ext(wizard_data).
`is_single_password()` is true if a wallet is already loaded,
while `wants_ext(wizard_data)` is false as `wants_ext()` depends on `seed_extend: True` in
`wizard_data` which only gets set after `apply()` of `WCHaveSeed` gets
called, however the evaluation of `WCHaveSeed` being the last view
happens before the view is shown.
By calling `checkIsLast()` in the validation timer of `WCHaveSeed` the
`last` property gets set again after `apply()` has been called, so
the view is guaranteed to correctly show either the `Finish` or `Next` button
after a seed has been entered.
qml: add signals for QEQRScanner and fallbacks, add QEBytes container type
so we can pass along byte arrays between QML and python, port qr scan
occurrences to new signals.
deletes the `seed_type` key from `wizard_data` in `WCWalletType` if it
is not explicitly set to prevent a stale value from a previous wizard
flow if the user goes back in the wizard and selects a different wallet
type instead of completing the wizard with the previously selected
wallet type.
This happens as the `apply()` function gets called with the
previously set radio button (e.g. 2fa) if the user goes back, if he then
selects multisig the `2fa_segwit` `seed_type` won't get cleared and
cause the exception later.
Example exception when first selecting 2fa, then going back and creating
a multisig wallet:
```
32.77 | E | gui.qml.qeapp.Exception_Hook | exception caught by crash reporter
Traceback (most recent call last):
File "/home/vagrant/electrum/electrum/gui/qml/qewizard.py", line 40, in submit
view = self.resolve_next(self._current.view, wdata)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/vagrant/electrum/electrum/wizard.py", line 78, in resolve_next
view_accept(wizard_data)
File "/home/vagrant/electrum/electrum/wizard.py", line 501, in maybe_master_pubkey
wizard_data['multisig_master_pubkey'] = self.keystore_from_data(wizard_data['wallet_type'], wizard_data).get_master_public_key()
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/vagrant/electrum/electrum/wizard.py", line 339, in keystore_from_data
return keystore.from_seed(data['seed'], passphrase=seed_extension, for_multisig=for_multisig)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/vagrant/electrum/electrum/keystore.py", line 1197, in from_seed
raise BitcoinException('Unexpected seed type {}'.format(repr(t)))
electrum.util.BitcoinException: Unexpected seed type '2fa_segwit'
```
Triggered by the following wizard stack:
```
30.94 | D | wizard | view=create_seed
30.94 | D | wizard | resolve_next view is confirm_seed
30.94 | D | wizard | wizard stack:
0: 0x7fdc6804ae80 - {}
1: 0x7fdc6ac61400 - {'wallet_name': 'wallet_1'}
2: 0x7fdc680d8a80 - {'seed_type': '2fa_segwit', 'wallet_name': 'wallet_1', 'wallet_type': 'multisig'}
3: 0x7fdc6804ab00 - {'multisig_cosigner_data': {}, 'multisig_participants': 2, 'multisig_signatures': 2, 'seed_type': '2fa_segwit', 'wallet_name': 'wallet_1', 'wallet_type': 'multisig'}
4: 0x7fdc6807f0c0 - {'keystore_type': 'createseed', 'multisig_cosigner_data': {}, 'multisig_participants': 2, 'multisig_signatures': 2, 'seed_type': '2fa_segwit', 'wallet_name': 'wallet_1', 'wallet_type': 'multisig'}
c: 0x7fdc6807c380 - {'keystore_type': 'createseed', 'multisig_cosigner_data': {}, 'multisig_participants': 2, 'multisig_signatures': 2, 'seed': '<redacted>', 'seed_extend': False, 'seed_extra_words': '<redacted>', 'seed_type': '2fa_segwit', 'seed_variant': 'electrum', 'wallet_name': 'wallet_1', 'wallet_type': 'multisig'}
30.94 | W | gui.qml.qeapp | next view: confirm_seed
```
disable the checkbox by default, so that if a user selects Enable Proxy
in the advanced network settings, and then just clicks next with the proxy
checkbox set, doesn't end up with a invalid proxy configuration which
doesn't connect to the server and has to be fixed manually.
user on bitcointalk [0] tried to create wallet with name "w/o 2FA".
Before this, one would only get an error after the last page of the wizard.
With this, the "Next" button does not even get enabled if the name does not look ok.
(and as in comment, maybe we should be even stricter re what is allowed)
[0]: https://bitcointalk.org/index.php?topic=5483514.msg63584789#msg63584789
fixes https://github.com/spesmilo/electrum/issues/8853
This is a bit ugly, but activeFocus is declared as final and cannot be overridden directly...
```
1.42 | W | gui.qml.qeapp | file:///home/user/wspace/electrum/electrum/gui/qml/components/controls/ElTextArea.qml:23:5: Cannot override FINAL property
```
- always store 'keystore_type' in cosigner data and use same types as main
- dont share 'hardware_device' in root of dict, but store for each cosigner
- properly return hardware keystore for hardware cosigners
