style: ruff format and the lint rules of the driver standard

Mechanical: ruff format, and ruff check --fix with the rule set every NAPALM
driver uses (E, F, I, UP, B at line length 100, Python 3.10). What ruff
cannot fix comes in the next commit.

tests/unit/test_driver.py

@@ -1,10 +1,10 @@
 """Unit tests for NetgearSmartDriver — no real device required."""
 
-import pytest
 from unittest.mock import MagicMock, patch
 
-from napalm_netgear.netgear_smart import NetgearSmartDriver
+import pytest
 
+from napalm_netgear.netgear_smart import NetgearSmartDriver
 
 # ---------------------------------------------------------------------------
 # Fixtures

tests/unit/test_ssh_host_key.py

@@ -24,7 +24,9 @@ HANDLER = "napalm_netgear.netgear_smart.ConnectHandler"
 
 def _device() -> MagicMock:
     device = MagicMock()
-    device.remote_conn_pre.get_transport.return_value.get_remote_server_key.return_value = SERVER_KEY
+    device.remote_conn_pre.get_transport.return_value.get_remote_server_key.return_value = (
+        SERVER_KEY
+    )
     return device