fix(selector): handle broken "Pass" cases

[fabiobozzo]

Test Case	Status
Optional Null Iterator	✅
Optional Iterator	✅
String Index	✅
Bytes Index [0]	✅
Bytes Index [1:]	✅
Array Slice [0:2]	✅
Array Slice [1:]	✅
Array Slice [:2]	✅
String Slice [0:2]	✅

CHANGELOG

• Added support for indexing into strings and byte arrays.
• Implemented array slicing for lists, strings, and byte arrays.
• Handled negative indices for array slicing and indexing.
• Added support for optional null iterators, returning an empty list node when applicable.
• Modified the iterator case to handle nested iterators correctly:
  • Recursively resolved remaining selector segments for nested lists.
  • Handled optional segments by skipping iterations when errors occur.
  • Appended single nodes and slices of nodes to the result appropriately.
• Updated the iterator case to handle non-list elements:
  • Skipped non-list elements when the next segment is optional.
  • Returned an error when the next segment is not optional and the current value is not a list.

---

Refactoring to reduce duplication and improve readability:

• Extracted common logic for resolving slice indices into a separate function.
• Switch statements to handle different segment types and node kinds.