fix: cast subject filtration to their true types

[prabhuteja12]

Description

• --task-subjects filtering breaks for tasks whose SUBJECTS are tuples with non-string elements. For e.g.

class MyFancyTask(BaseTask[tuple[str, int, str]])
    SUBJECTS = [("ctx1", 123, "single")]

• When creating a task with with_overwrite, passing custom_subject="ctx1,123,single" and BaseTask._filter_task_subjects splits that string on , to build a tuple to match against SUBJECTS -> ("ctx1", "123", "single"). Every part is a str, including "123". But the real subject has an int there: ("ctx1", 123, "single"). Python's "123" == 123 is False, so the match fails and you get

AssertionError: Subject part 123 not found in task MyFancyTask

• This only breaks for tuple subjects with a non-str position. It's been invisible because every other tuple-subject task (e.g. GlobalMMLU) uses all-str tuples like ("EN_US", "topic1"), where str == str just works.

Fix

• Infer the real type at each tuple position from an actual subject (type(SUBJECTS[0][i])) and cast each comma-separated part back to it before comparing