feat: do not check class in @covers exists

[simPod]

PHPStan checks for that now

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.14 :warning:

Comparison is base (c06d563) 97.95% compared to head (5357e4c) 97.82%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #69 +/- ## ============================================ - Coverage 97.95% 97.82% -0.14% + Complexity 54 52 -2 ============================================ Files 6 6 Lines 196 184 -12 ============================================ - Hits 192 180 -12 Misses 4 4 ``` | [Impacted Files](https://codecov.io/gh/cdn77/TestUtils/pull/69?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cdn77) | Coverage Δ | | |---|---|---| | [...tCheck/EveryTestHasSameNamespaceAsCoveredClass.php](https://codecov.io/gh/cdn77/TestUtils/pull/69?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cdn77#diff-c3JjL1Rlc3RDaGVjay9FdmVyeVRlc3RIYXNTYW1lTmFtZXNwYWNlQXNDb3ZlcmVkQ2xhc3MucGhw) | `95.23% <100.00%> (-1.06%)` | :arrow_down: | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cdn77). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=cdn77)

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