refactor(typing): reduce type ignores in api.py (vega#3480)

* refactor(typing): reduce type ignores in `api.py`

* feat(typing): adds `_is_undefined` guard

Direct copy from another PR, but is helpful here https://github.com/dangotbanned/altair/blob/d607c70824860ef3478d7d3996d26dc516d69369/altair/vegalite/v5/api.py#L504

* fix(typing): `ignore[index]` from vega#3455

* fix(typing): `[ignore[arg-type]` from vega#3452

* refactor(typing): use `_is_undefined` in some cases

* refactor: reduce code duplication in `Chart.to_dict`

* fix(typing): Recover `TopLevelMixin.resolve_` return types

I removed these in 6adf564 due to how complex they were getting, but both `mypy` and `pyright` seem happy with this solution

* fix(typing): narrow annotated types for `_check_if_valid_subspec`

Following investigation during vega#3480 (comment)

* refactor: remove unused `_wrapper_classes` argument from `SchemaBase`

Fixes:
- vega#3480 (comment)
- vega#3480 (comment)
- vega#3480 (comment)

altair/utils/schemapi.py

@@ -1087,10 +1087,7 @@ def _default_wrapper_classes(cls) -> Iterator[type[SchemaBase]]:
 
     @classmethod
     def from_dict(
-        cls: type[TSchemaBase],
-        dct: dict[str, Any],
-        validate: bool = True,
-        _wrapper_classes: Iterable[type[SchemaBase]] | None = None,
+        cls: type[TSchemaBase], dct: dict[str, Any], validate: bool = True
     ) -> TSchemaBase:
         """Construct class from a dictionary representation
 
@@ -1100,10 +1097,6 @@ def from_dict(
             The dict from which to construct the class
         validate : boolean
             If True (default), then validate the input against the schema.
-        _wrapper_classes : iterable (optional)
-            The set of SchemaBase classes to use when constructing wrappers
-            of the dict inputs. If not specified, the result of
-            cls._default_wrapper_classes will be used.
 
         Returns
         -------
@@ -1117,9 +1110,7 @@ def from_dict(
         """
         if validate:
             cls.validate(dct)
-        if _wrapper_classes is None:
-            _wrapper_classes = cls._default_wrapper_classes()
-        converter = _FromDict(_wrapper_classes)
+        converter = _FromDict(cls._default_wrapper_classes())
         return converter.from_dict(dct, cls)
 
     @classmethod