Revisit mypy setup

[merelcht]

Description

Part of #2156

Development notes

• Removed mypy from pre-commit setup and run it as part of make lint in a separate step instead
• Fixed or ignored all issues flagged when running mypy kedro
• Quite a lot of issues came from re-assigning the same variable name making the type incorrect.
• Next step is to run mypy --strict, see follow up PRs:
  • Fix issues flagged by mypy strict  #3490
  • Fix mypy strict issues #2 #3497
  • Fix mypy error postitional only #3498

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Checklist

• Read the contributing guidelines
• Signed off each commit with a Developer Certificate of Origin (DCO)
• Opened this PR as a 'Draft Pull Request' if it is work-in-progress
• Updated the documentation to reflect the code changes
• Added a description of this change in the RELEASE.md file
• Added tests to cover my changes
• Checked if this change will affect Kedro-Viz, and if so, communicated that with the Viz team

[noklam]

Nice work! Approved with one non-blocking comment about dependencies.

[AhdraMeraliQB]

Looks great! Love that we're not overwriting variable names anymore, it's a lot easier to read. Just a (non-blocking) QQ - sometimes we have var: Type | None and other times var: None | Type - is there a rule or convention we should apply in terms of what should go first? Or alternatively, is consistency not a priority for typing?

[DimedS]

Thank you, @merelcht !

[astrojuanlu]

+1 for var: Type | None rather than None | Type!

[merelcht]

Looks great! Love that we're not overwriting variable names anymore, it's a lot easier to read. Just a (non-blocking) QQ - sometimes we have var: Type | None and other times var: None | Type - is there a rule or convention we should apply in terms of what should go first? Or alternatively, is consistency not a priority for typing?

Ha yeah good spot. I started on this with None | Type and later decided I preferred the other way around, but forgot to change that everywhere. Will do that before merging!