Fix lint errors

aqt/commercial.py

@@ -21,7 +21,9 @@ class QtPackageInfo:
 
 
 class QtPackageManager:
-    def __init__(self, arch: str, version: Version, target: str, username: str = None, password: str = None):
+    def __init__(
+        self, arch: str, version: Version, target: str, username: Optional[str] = None, password: Optional[str] = None
+    ):
         self.arch = arch
         self.version = version
         self.target = target

aqt/installer.py

@@ -930,13 +930,10 @@ def run_list_qt_commercial(self, args) -> None:
 
         except Exception as e:
             self.logger.error(f"Failed to list Qt commercial packages: {e}")
-            return 1
         finally:
             # Clean up
             Settings.qt_installer_cleanup()
 
-        return 0
-
     def _warn_on_deprecated_command(self, old_name: str, new_name: str) -> None:
         self.logger.warning(
             f"The command '{old_name}' is deprecated and marked for removal in a future version of aqt.\n"