feat(langchain_v1): represent server side tools in modifyModelRequest and update tool handling (#33274)
* Add server side tools to modifyModelRequest (represented as dicts)
* Update some of the logic in terms of which tools are bound to ToolNode
* We still have a constraint on changing the response format dynamically
when using tool strategy. structured_output_tools are being using in
some of the edges. The code is now raising an exception to explain that
it's a limitation of the implementation. (We can add support later.)