Use max_passages and min_words_per_passage params in DocumentChunker.

Bug: b/343759942
Change-Id: I18289be72b46a732f6ccde5f5099aa6aa9adf9f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5594935


Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Orin Jaworski <orinj@chromium.org>
Commit-Queue: Zekun Jiang <zekunjiang@google.com>
Cr-Commit-Position: refs/heads/main@{#1311051}