## Background

faced the issue while implementing #13157 - for multiturn conversation,
the item Ids weren't properly being mapped within aisdk and there was a
mismatch between what we were sending to the openai api and what was
expected.

we were attching the same tool call id as the `tool-call` object to the
`tool-result` which caused duplicate ID found errors + incorrect ids
sent for certain parts

## Summary

- since the item_id for tool_search_output is propagated via
providerMetadata - we ensure the providerMetadata is preserved through
the UI stream.
- similar change needed for generate text as well

## Manual Verification

will be done in #13157 

## Checklist

- [x] Tests have been added / updated (for bug fixes / features)
- [ ] Documentation has been added / updated (for bug fixes / features)
- [x] A _patch_ changeset for relevant packages has been added (for bug
fixes / features - run `pnpm changeset` in the project root)
- [x] I have reviewed this pull request (self-review)