bugfix: assert walrus (":=") combo side-eff. breaks w/ asserts disabled

```
$ python3 -O
Python 3.10.6 (main, Mar 10 2023, 10:55:28) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> assert (x := 2)
>>> x
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NameError: name 'x' is not defined
```

pity. it looked to be a neat and concise pattern.

electrum/plugins/bitbox02/bitbox02.py

@@ -444,7 +444,8 @@ class BitBox02Client(HardwareClientBase):
                 }
             )
 
-            assert (desc := txin.script_descriptor)
+            desc = txin.script_descriptor
+            assert desc
             if tx_script_type is None:
                 tx_script_type = desc.to_legacy_electrum_script_type()
             elif tx_script_type != desc.to_legacy_electrum_script_type():

electrum/plugins/digitalbitbox/digitalbitbox.py

@@ -528,7 +528,8 @@ class DigitalBitbox_KeyStore(Hardware_KeyStore):
                 if txin.is_coinbase_input():
                     self.give_error("Coinbase not supported") # should never happen
 
-                assert (desc := txin.script_descriptor)
+                desc = txin.script_descriptor
+                assert desc
                 if desc.to_legacy_electrum_script_type() != 'p2pkh':
                     p2pkhTransaction = False
 

electrum/plugins/jade/jade.py

@@ -280,7 +280,8 @@ class Jade_KeyStore(Hardware_KeyStore):
             change = [None] * len(tx.outputs())
             for index, txout in enumerate(tx.outputs()):
                 if txout.is_mine and txout.is_change:
-                    assert (desc := txout.script_descriptor)
+                    desc = txout.script_descriptor
+                    assert desc
                     if is_multisig:
                         # Multisig - wallet details must be registered on Jade hw
                         multisig_name = _register_multisig_wallet(wallet, self, txout.address)

electrum/plugins/keepkey/keepkey.py

@@ -371,7 +371,8 @@ class KeepKeyPlugin(HW_PluginBase):
                     assert isinstance(tx, PartialTransaction)
                     assert isinstance(txin, PartialTxInput)
                     assert keystore
-                    assert (desc := txin.script_descriptor)
+                    desc = txin.script_descriptor
+                    assert desc
                     if multi := desc.get_simple_multisig():
                         multisig = self._make_multisig(multi)
                     else:
@@ -417,7 +418,8 @@ class KeepKeyPlugin(HW_PluginBase):
     def tx_outputs(self, tx: PartialTransaction, *, keystore: 'KeepKey_KeyStore'):
 
         def create_output_by_derivation():
-            assert (desc := txout.script_descriptor)
+            desc = txout.script_descriptor
+            assert desc
             script_type = self.get_keepkey_output_script_type(desc.to_legacy_electrum_script_type())
             if multi := desc.get_simple_multisig():
                 multisig = self._make_multisig(multi)

electrum/plugins/safe_t/safe_t.py

@@ -341,7 +341,8 @@ class SafeTPlugin(HW_PluginBase):
                     assert isinstance(tx, PartialTransaction)
                     assert isinstance(txin, PartialTxInput)
                     assert keystore
-                    assert (desc := txin.script_descriptor)
+                    desc = txin.script_descriptor
+                    assert desc
                     if multi := desc.get_simple_multisig():
                         multisig = self._make_multisig(multi)
                     else:
@@ -387,7 +388,8 @@ class SafeTPlugin(HW_PluginBase):
     def tx_outputs(self, tx: PartialTransaction, *, keystore: 'SafeTKeyStore'):
 
         def create_output_by_derivation():
-            assert (desc := txout.script_descriptor)
+            desc = txout.script_descriptor
+            assert desc
             script_type = self.get_safet_output_script_type(desc.to_legacy_electrum_script_type())
             if multi := desc.get_simple_multisig():
                 multisig = self._make_multisig(multi)

electrum/plugins/trezor/trezor.py

@@ -412,7 +412,8 @@ class TrezorPlugin(HW_PluginBase):
                     assert isinstance(tx, PartialTransaction)
                     assert isinstance(txin, PartialTxInput)
                     assert keystore
-                    assert (desc := txin.script_descriptor)
+                    desc = txin.script_descriptor
+                    assert desc
                     if multi := desc.get_simple_multisig():
                         txinputtype.multisig = self._make_multisig(multi)
                     txinputtype.script_type = self.get_trezor_input_script_type(desc.to_legacy_electrum_script_type())
@@ -444,7 +445,8 @@ class TrezorPlugin(HW_PluginBase):
     def tx_outputs(self, tx: PartialTransaction, *, keystore: 'TrezorKeyStore'):
 
         def create_output_by_derivation():
-            assert (desc := txout.script_descriptor)
+            desc = txout.script_descriptor
+            assert desc
             script_type = self.get_trezor_output_script_type(desc.to_legacy_electrum_script_type())
             if multi := desc.get_simple_multisig():
                 multisig = self._make_multisig(multi)