**Summary**
Add `metadata.is_continuation = True` to metadata of second-and-later
text-split chunks formed from an oversized non-table element. Previously
this metadata was only present on text-split `TableChunk` elements.
This enables downstream filtering of intentionally redundant metadata on
chunk elements that may not be desired for all purposes.
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Co-authored-by: scanny <scanny@users.noreply.github.com>