[Core feature] Generic alias support

[wild-endeavor]

Motivation: Why do you think this is important?

flytekit currently does not have generic alias support. That is, while this works

@task
def t1(nodelist: List[int] | None = None):
    print(nodelist)

this does not

@task
def t2(nodelist: list[int] | None = None):
    print(nodelist)

If you try to run this, you get the error isinstance() argument 2 cannot be a parameterized generic that's mentioned in docs for standard types.

Propose: Link/Inline OR Additional context

The usage of isinstance is currently coming from the assert_type call in the type engine. Kinda worked around that in here https://github.com/flyteorg/flytekit/pull/2743/files and got the trivial case above working but additional tests and more complex cases need to be considered.

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes

[wild-endeavor]

Ensure that Optional[list[int]] also works.

[blaketastic2]

We're actually seeing an issue relating to list[str] when the code goes through the ListTransformer path. https://github.com/flyteorg/flytekit/blob/effa4431a3de7b7c03b62b0bab7eb949311e00ad/flytekit/core/type_engine.py#L1331-L1370