[12.x] Add parameter validation to Collection::sliding() method.

[Button99]

This PR adds parameter validations to Collection::sliding() and LazyCollection::sliding() methods.
The methods will throw an InvalidArgumentException when the $steps and $size parameters are <1.

With that way we have 2 issues fixed.

1. Size of 0 produced empty chunks.

// Before fix:
Collection::times(5)->sliding(0, 1)->toArray();
// Result: [[], [], [], [], [], []]

// Mathematical calculation:
// $chunks = floor((count - size) / step) + 1
// $chunks = floor((5 - 0) / 1) + 1 // 6
// Each chunk has size 0, resulting in 6 empty arrays

2. Step of 0 caused DivisionByZeroError

  // Before fix:
  Collection::times(5)->sliding(2, 0)->toArray();
  // Result: DivisionByZeroError

  // Mathematical calculation:
  // $chunks = floor((5 - 2) / 0) + 1 = DivisionByZeroError

Thank you.

[shaedrich]

You can narrow this further down then:

Suggested change

	* @param int $size
	* @param int $step
	* @param positive-int $size
	* @param positive-int $step

[shaedrich]

You might even reflect that in the return type:

Suggested change

	* @return static<int, static>
	* @return $size is positive-int ? $step is positive-int ? static<int, static> : never : never