[11.x] fix 'parsePipeString' in pipeline helper

[igzard]

Fix: Ensure parsePipeString() Returns an Empty Array Instead of an Empty String

Return Value of parsePipeString():

If the character is not present in the $pipe variable, explode(':', $pipe, 2) returns an array with a single element: [$pipe].
While array_pad() extends the array, the second value will be an empty string ('') instead of an empty array ([]).
This causes an issue when calling explode(',', $parameters), as explode(',', '') returns [''], not [].