Fix reagent LRScheduler tests

[janeyx99]

Summary: I recently exposed LRScheduler as a public endpoint as that is the right direction for users. This diff adds LRScheduler as a torch lr scheduler, which it is.

Would fix test errors such as https://www.internalfb.com/intern/testinfra/diagnostics/281475249445597.562950030008200.1668085134/, which were introduced by my landing of D41109279.

Created from CodeHub with https://fburl.com/edit-in-codehub

Reviewed By: czxttkl

Differential Revision: D41187073

[facebook-github-bot]

This pull request was exported from Phabricator. Differential Revision: D41187073

[codecov-commenter]

Codecov Report

Base: 87.64% // Head: 87.64% // No change to project coverage :thumbsup:

Coverage data is based on head (8b3e5a4) compared to base (9de19b6). Patch coverage: 100.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #697 +/- ## ======================================= Coverage 87.64% 87.64% ======================================= Files 365 365 Lines 23687 23687 Branches 44 44 ======================================= Hits 20760 20760 Misses 2901 2901 Partials 26 26 ``` | [Impacted Files](https://codecov.io/gh/facebookresearch/ReAgent/pull/697?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=facebookresearch) | Coverage Δ | | |---|---|---| | [reagent/optimizer/utils.py](https://codecov.io/gh/facebookresearch/ReAgent/pull/697/diff?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=facebookresearch#diff-cmVhZ2VudC9vcHRpbWl6ZXIvdXRpbHMucHk=) | `100.00% <100.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=facebookresearch). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=facebookresearch)

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