feat(interactive): Support real long_text data type in storage

[zhanglei1949]

Currently for LongText data type, we implement it via a VAR_CHAR(256). However, we should be able to support a real LongText implementation.

[longbinlai]

And, make sure the current users know they are actually using VAR_CHAR(256)

[github-actions]

/cc @zhanglei1949, this issus/pr has had no activity for for a long time, could you folks help to review the status ?
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