Adding withStructuredOutput support to BedrockChat now that AWS supports tool calling

[pjdon]

Checked

• I searched existing ideas and did not find a similar one
• I added a very descriptive title
• I've clearly described the feature request and motivation for it

Feature request

AWS has recently enabled tool calling for bedrock: Tool use (function calling) - Amazon Bedrock

Currently the BedrockChat interface does not support structured output as until recently the functionality did not exist in bedrock.

The proposal is to implement withStructuredOutput to work the same as in other interfaces that currently support it: https://js.langchain.com/v0.1/docs/use_cases/extraction/quickstart/

Motivation

There is a parallel issue opened for the Python implementation
langchain-ai/langchain#22701

Proposal (If applicable)

No response

[pjdon]

The contribution guide indicates that

We aim to keep the same core APIs between the Python and JS versions of LangChain, where possible

Does a submitted PR that implements this feature have to also point to an existing implemention of the feature in the Python LC version before being accepted?