refactor: fix phpstan no type specified ValidationModelTest

[adiprsa]

Description
See #7731

• Add PHPDoc type

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value (without duplication)
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[mergeable]

Hi there, adiprsa! 👋

Thank you for sending this PR!

We expect the following in all Pull Requests (PRs).

• PRs must be sent to the appropriate branch
• All git commits must be GPG-signed
• Must follow our style guide
• Be commented in the PHP source file
• Be documented in the user guide
• Be unit tested
• Pass all checks in GitHub Actions

Important

We expect all code changes or bug-fixes to be accompanied by one or more tests added to our test suite to prove the code works.

If pull requests do not comply with the above, they will likely be closed. Since we are a team of volunteers, we don't have any more time to work
on the framework than you do. Please make it as painless for your contributions to be included as possible.

See https://github.com/codeigniter4/CodeIgniter4/blob/develop/contributing/pull_request.md

Sincerely, the mergeable bot 🤖

[adiprsa]

help, i made mistake commit without gpg
first without gpg, second amend with gpg, then appear pull merge branch

the commit log become mess

how i resolve this?

[paulbalandan]

I do not see the merge commit here in GitHub.

[michalsn]

@adiprsa See here: https://github.com/codeigniter4/CodeIgniter4/blob/develop/contributing/workflow.md#gpg-signing-old-commits

[michalsn]

Thank you @adiprsa