Flaky video test

[prabhat00155]

https://app.circleci.com/pipelines/github/pytorch/vision/12610/workflows/9ab703cc-7277-4f05-9079-d2ace1dc94b4/jobs/998680

https://app.circleci.com/pipelines/github/pytorch/vision/13889/workflows/62bf350f-c0a9-4506-a09f-9dbc56b7cf1b/jobs/1117960

Traceback (most recent call last):
  File "/root/project/test/test_videoapi.py", line 75, in test_frame_reading
    assert mean_delta.item() < 2.5
AssertionError: assert 2.513227701187134 < 2.5
 +  where 2.513227701187134 = <built-in method item of Tensor object at 0x7f3941851ea8>()
 +    where <built-in method item of Tensor object at 0x7f3941851ea8> = tensor(2.5132).item

cc @pmeier @seemethere

[prabhat00155]

Fixed by #5192.