Update littlefs from 2.4.0 -> 2.9.3

[mikee47]

This PR updates the Sming-LittleFS library, which implements IFS for the littlefs file system.

The library still uses a fork of littlefs because it adds attribute enumeration support - see upstream PR request. This has now been rebased on version 2.9.3 - see releases for details of all the changes. Here's a (non-exhaustive) summary:

• Improved RAM usage
• Improved performance
• v2.5.0 removed all recursion
• v2.6.0 bump the on-disk minor version of littlefs from lfs2.0 -> lfs2.1. "This change is backwards-compatible, but after the first write with the new version, the image on disk will no longer be mountable by older versions of littlefs."
• v2.7.0 Add lfs_fs_stat as an analog for the POSIX stavfs. This isn't currently used by Sming-LittleFS.
• v2.9.0 rename now returns LFS_ERR_NOTDIR if the source is a regular file and the destination is a directory. This better aligns with POSIX.

There are no functional changes to the library, but the samples have been simplified. An additional sample has been added to assess wear levelling behaviour (as a result of discussion #2771).

[what-the-diff]

PR Summary

• Updated LittleFS Submodule
  The LittleFS component, a key module in our system, has been updated to a more recent version. This update will enhance the performance and reliability of our software by incorporating the latest improvements and fixes from the LittleFS project.