Fix issues in end-to-end tests:
1. **Split column groups based on schema**, rather than estimating by
average chunk row size. **Ensure column group consistency within a
segment**, to avoid errors caused by loading multiple column group
chunks simultaneously.
2. **Use sorted segmentId** when generating the stats binlog path, to
ensure consistent and correct file path resolution.
3. **Determine field IDs as follows**:
For multi-column column groups, retrieve the field ID list from
metadata.
For single-column column groups, use the column group ID directly as the
field ID.
related: #39173fix: #42862
---------
Signed-off-by: shaoting-huang <shaoting.huang@zilliz.com>
sthuang