[Carbon] Skip first class callable on Carbon rules

[samsonasik]

to avoid error:

There was 1 failure:

1) Rector\Tests\Carbon\Rector\FuncCall\DateFuncCallToCarbonRector\DateFuncCallToCarbonRectorTest::test with data set #0 ('/Users/samsonasik/www/rector-...hp.inc')
assert(!$this->isFirstClassCallable())

on first class callable.

[samsonasik]

All checks have passed 🎉 @TomasVotruba I am merging it ;)

[TomasVotruba]

Thank you as alwas 👍 😉