docs: remove incorrect @internal in TestResponse

[kenjis]

Description
TestResponse is not internal, but devs use it.
But php-cs-fixer force to add it. How can we remove it?

Checklist:

• Securely signed commits
• Component(s) with PHPDoc blocks, only if necessary or adds value
• Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[MGatner]

Well, that was odd. But I agree with the approach: add TestResponse to the CS Fixer exemption list for now, and maybe include a note in a file-level comment. This file is unlikely to change and also have style issues, but we may be creating static analysis problems for devs downstream.

[paulbalandan]

php-cs-fixer is adding the @internal phpdoc because it extends TestCase and thinks it is a test.

[paulbalandan]

Does TestResponse really need to extend TestCase? I think we can make it a class of its own with no extends. The use for extending TestCase, from what I can see, is to use the assertions. Since those are actually static, we can directly use them instead.

[kenjis]

TestResponse is not a kind of TestCase.
So it should not extend TestCase.

[MGatner]

Agreed! That was my mistake, I believe. Static assertions would be way better.

[paulbalandan]

Closing in favor of #8264