ProductOpener::NBooleans - normalize boolean values sent in various formats
Over the years, we have used different ways to store boolean values in products and to get their values from the API. This function normalizes the value to a boolean value (true or false) and returns it.
True values: - true (boolean type) - "true" string - 1 (integer or string) - "checked", "on" (set by HTML checkboxes)
False values: - false (boolean type) - "false" string - 0 (integer) - "" empty string - undef - any other values that are not considered true values