Fix: Add support for listpack encoding in Redis 7.0+

[salkhwlani]

Problem

The scanner crashes when encountering keys with listpack encoding:

ValueError: Invalid encoding b'listpack' given

This occurs when scanning Redis 7.0+ instances, as the tool doesn't recognize the newer listpack encoding type.

Solution

Added support for the listpack encoding type in redis_types.py:
- Added REDIS_ENCODING_ID_LISTPACK = 9 constant
- Added b'listpack': REDIS_ENCODING_ID_LISTPACK mapping to REDIS_ENCODING_STR_TO_ID_LIB
- Included it in REDIS_ENCODING_ID_ALL list

Background

listpack is a more memory-efficient encoding introduced in Redis 7.0 as a replacement for ziplist in certain data structures (hashes, sorted sets, and streams).

Testing

Tested against Redis 7.0+ instance with keys using listpack encoding. The scanner now completes successfully without errors.