Add ChatBedrockConverse to the playground

[thiagotps]

Feature request

Add ChatBedrockConverse from langchain-aws to the playground, with support for doing tool calling.

Motivation

Currently the playground doesn't allow the use of the new ChatBedrockConverse class of langchain-aws. This is particularly important for us because we are using boto3 converse api for doing tool calling, and we would like to experiment with tool calling in the playground too.