[4.x] Improve type safety for test environment

[SimonFrings]

This pull request adds some missing Promise v3 template types that have been reported by PHPStan. The same changes should also be applied to the 3.x branch, so once this is merged I will create a follow-up PR to do so.

Builds on top of reactphp/promise#247, clue/framework-x/pull/235, #76 and others

[WyriHaximus]

@SimonFrings PHPStan 1.11 came out a couple of days ago, did you run this again it? I know updating versions will always be a thing. But 1.11 introduces error identifiers which would make the ignore lines a bit cleaner and more specific what is being ignored: https://phpstan.org/blog/phpstan-1-11-errors-identifiers-phpstan-pro-reboot

[SimonFrings]

I updated the PR a bit, happy about your input on this 👍

PHPStan 1.11 came out a couple of days ago, did you run this again it? know updating versions will always be a thing. But 1.11 introduces error identifiers which would make the ignore lines a bit cleaner and more specific what is being ignored: […]

Tried this but didn't help with the problem I was running into (see below). We could go on PHPStan 11 but I think this is better suite for a follow-up PR.

[clue]

@SimonFrings Thanks for the update, changes LGTM!

The work-around looks good enough to me, but glad you've reported this upstream (phpstan/phpstan#11032) so we can revisit this in the future 👍