[10.x] Fix breaking changes in before validation

[MrPunyapal]

I had a PR #49871 to fix Issue #49863 but from this #49871 (comment) conversation it looks breaking change.

if it is a breaking change then this PR will solve it. added tests for it too.

$v = new Validator($trans, ['y' => '1970-01-01'], ['x' => 'nullable|date', 'y' => 'nullable|date|after:x']);
$this->assertTrue($v->passes());

$v = new Validator($trans, ['y' => '1970-01-01'], ['x' => 'nullable|date', 'y' => 'nullable|date|before:x']);
$this->assertTrue($v->passes());

[MrPunyapal]

@calebdw 🤔

[calebdw]

I don't believe was ever true, so should be removed (or just reverse the condition). Essentially every date is "after" null

[MrPunyapal]

so it can be after null but cannot be before null? 👀

[MrPunyapal]

I don't believe was ever true, so should be removed (or just reverse the condition). Essentially every date is "after" null

okay before:x test was failing before adding all of those conditions too 🫡

[calebdw]

But after:x was not? Why did you close?

[MrPunyapal]

by mistakenly added with old branch