fix(core): resolve PHPStan iterable type errors (#8732)

[Chucho-Kun]

Description
PHPStan errors were eliminated by reducing the baseline to 1200 errors as part of my contribution to the good first issue label
The modifications is in the branch fix/issue-8732-basemodel-types and were validated with the following command

composer phpstan:check -- --memory-limit=512M

[mergeable]

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[michalsn]

Thank you. Please omit any modifications related to Kint, since it was already updated in #9802.

[neznaika0]

For the BasicModel, I recently closed PR. We could not agree on the rules of phpDoc - phpstan or simple types.

I stopped correcting the typing.

[github-actions]

👋 Hi, @Chucho-Kun!

We detected conflicts in your PR against the base branch 🙊
You may want to sync 🔄 your branch with upstream!

Ref: Syncing Your Branch

[paulbalandan]

Thanks for picking up #8732, @Chucho-Kun. Trimming the missingType.iterableValue baseline is exactly the kind of incremental cleanup we want, and the effort here is appreciated.

Unfortunately, most of this PR has been overtaken by changes that have already landed on develop, and a few of the proposed annotations would walk back to looser types than what we now ship.

Given that this has been open for ~6 months with no movement, I'm constrained to close this PR for now. Happy for you to open a refreshed PR taking a smaller slice at the baseline. Thanks again for the contribution.