Fix typing annotations for the ipu strategy

[HalestormAI]

Fixes mypy errors attributed to pytorch_lightning/strategies/ipu.py for issue #13445

removed module name from pyproject.toml [tool.mypy.overrides]
resolved discrepencies for `Optional` returned objects
fixed missing and incorrect type hints.

Part of #13445

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[HalestormAI]

Hmm, ok the mypy test was passing locally, perhaps missed something when I rebased. Will fix.

[codecov]

Codecov Report

Merging #13786 (ed96cef) into master (ee4233b) will increase coverage by 15%.
The diff coverage is 62%.

❗ Current head ed96cef differs from pull request most recent head bc6f314. Consider uploading reports for the commit bc6f314 to get more accurate results

@@            Coverage Diff            @@
##           master   #13786     +/-   ##
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+ Coverage      61%      76%    +15%     
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  Files         341      341             
  Lines       26564    26620     +56     
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+ Hits        16214    20239   +4025     
+ Misses      10350     6381   -3969     

[otaj]

Hi @HalestormAI, do you need some help with finalizing this PR? 💪

[HalestormAI]

Yes please - went round in circles a few times trying to resolve the typing clash on lightning_module - haven't yet found a way to do it. Been tied up with work things last week so haven't had much chance to revisit

[otaj]

LGTM! I added a small commit resolving those last couple errors. We'll see how the IPU CI likes it 💪

[otaj]

Adding a bunch of asserts at correct places seemed to help, so now we're green with the tests again 🎉

[HalestormAI]

Great! Thanks @otaj . I was trying to avoid all the asserts, but I guess that's the only way!

[HalestormAI]

Should I update branch then create review? Do you prefer merge or rebase to line this up with master?

[otaj]

We are "merge" folks :) There's also a button "Update branch" (I don't know if you have it as well), which will merge master for you if there are no conflicts :)

[HalestormAI]

Thanks @otaj - I've updated the branch and fixed the suggestion above. Once the CI completes I'll put it in for review

[awaelchli]

Solid