Related to milvus-io/milvus-sdk-go#818
This PR make Row-based insert data parsing embedded struct as flatten
fields instead.
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>
See also #33457
Also add `max_length` tag for specify varchar field max length attribute
from tagging
Signed-off-by: Congqi Xia <congqi.xia@zilliz.com>