Fix sort direction ignored in GeoSearchStoreCommandArgs.sort().

[yeonsu00]

Problem

GeoSearchStoreCommandArgs.sort(Direction) always assigned Direction.ASC
regardless of the provided argument:

public GeoSearchStoreCommandArgs sort(Direction direction) {
    Assert.notNull(direction, "Sort direction must not be null");
    sortDirection = Direction.ASC; // direction parameter ignored
    return this;
}

This caused sortDescending() to have no effect, and the SORT DESC flag
was never passed to the underlying Redis GEOSEARCHSTORE command in either
Lettuce or Jedis drivers.

The equivalent method in GeoSearchCommandArgs is implemented correctly and
served as a reference.

Fix

Assign the provided direction argument directly:

sortDirection = direction;

Testing

Added integration test geoSearchAndStoreShouldRespectSortDirection that:

• Adds three members at different distances from a reference point (Palermo, Agrigento, Catania)
• Calls searchAndStore with sortDescending().limit(1)
• Verifies that only the farthest member (Catania) is stored in the destination key

Closes #3342

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