Add `require_torch` to 2 pipeline tests
# What does this PR do?

The 2 tests are for `pytorch`, but in TF pipeline test CI job (where `torch` is not available), it runs with TF models.
This is not expected.

Before #20149, these 2 tests are decorated with `require_torch_scatter`. After that PR, the tests try to run with TF, but failed with `TFTapasMainLayer requires the tensorflow_probability library but it was not found in your environment.`
(this is another thing to fix in docker file)
_The documentation is not available anymore as the PR was closed or merged._