[Reland] Update mypy to 1.4.1 (#105227)

This PR re-lands
- [Typing] Fix PEP 484 Violation (#105022)
- Update mypy to 1.4.1 (#91983)

That were reverted due to the conflict with internal source repo.

Mostly fixes for PEP-484 violation (i.e. when default arg is set to None, but type is not annotated as optional)
Plus few real fixes:
  - Add missing `_get_upgraders_entry_map` to `torch/_C/__init__.pyi`
  - Add missing return statement to `torch._export. deserialize_graph`
  - Fix error message in `torch.ao.ns.fx.weight_utils.get_lstm_mod_weights`
  - Add assert it `torch/optim/optimizer.py` that Optional list is not None
TODO (in followup PR):
  - Fix erroneous `isinstance` check in `torch/ao/quantization/_pt2e/qat_utils.py`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/105227
Approved by: https://github.com/atalman, https://github.com/albanD, https://github.com/Skylion007

test/test_futures.py

@@ -21,7 +21,7 @@ class TestFuture(TestCase):
         error_msg = "Intentional Value Error"
         value_error = ValueError(error_msg)
 
-        f = Future[T]()
+        f = Future[T]()  # type: ignore[valid-type]
         # Set exception
         f.set_exception(value_error)
         # Exception should throw on wait
@@ -29,7 +29,7 @@ class TestFuture(TestCase):
             f.wait()
 
         # Exception should also throw on value
-        f = Future[T]()
+        f = Future[T]()  # type: ignore[valid-type]
         f.set_exception(value_error)
         with self.assertRaisesRegex(ValueError, "Intentional"):
             f.value()
@@ -37,7 +37,7 @@ class TestFuture(TestCase):
         def cb(fut):
             fut.value()
 
-        f = Future[T]()
+        f = Future[T]()  # type: ignore[valid-type]
         f.set_exception(value_error)
 
         with self.assertRaisesRegex(RuntimeError, "Got the following error"):
@@ -54,7 +54,7 @@ class TestFuture(TestCase):
             with self.assertRaisesRegex(ValueError, "Intentional"):
                 f.wait()
 
-        f = Future[T]()
+        f = Future[T]()  # type: ignore[valid-type]
         t = threading.Thread(target=wait_future, args=(f, ))
         t.start()
         f.set_exception(value_error)
@@ -68,7 +68,7 @@ class TestFuture(TestCase):
             with self.assertRaisesRegex(RuntimeError, "Got the following error"):
                 fut.wait()
 
-        f = Future[T]()
+        f = Future[T]()  # type: ignore[valid-type]
         t = threading.Thread(target=then_future, args=(f, ))
         t.start()
         f.set_exception(value_error)