Update mypy, fix associated errors

Author: alec-bike

altair/vegalite/v6/api.py

@@ -5170,7 +5170,7 @@ def _needs_name(subchart: ChartType) -> bool:
         return False
 
     # Variable parameters won't receive a views property.
-    return not all(isinstance(p, core.VariableParameter) for p in subchart.params)  # type: ignore
+    return not all(isinstance(p, core.VariableParameter) for p in subchart.params)
 
 
 # Convert SelectionParameters to TopLevelSelectionParameters with a views property.