Enable E402 ruff check

[robertapplin]

Description of work

This PR fixes any remaining ruff E402 errors, documented here:
https://docs.astral.sh/ruff/rules/module-import-not-at-top-of-file/

It also enables this check to run on all pull requests.

To test:

Code review - check that all changes look reasonable

Run ruff locally on all files using the following terminal command

pre-commit run ruff --all-files

Reviewer

Please comment on the points listed below (full description).
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Code Review

• Is the code of an acceptable quality?
• Does the code conform to the coding standards?
• Are the unit tests small and test the class in isolation?
• If there is GUI work does it follow the GUI standards?
• If there are changes in the release notes then do they describe the changes appropriately?
• Do the release notes conform to the release notes guide?

Functional Tests

• Do changes function as described? Add comments below that describe the tests performed?
• Do the changes handle unexpected situations, e.g. bad input?
• Has the relevant (user and developer) documentation been added/updated?

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Gatekeeper

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[github-actions]

👋 Hi, @robertapplin,

Conflicts have been detected against the base branch. Please rebase your branch against the base branch.

[peterfpeterson]

Thanks for moving the suppressions into individual files