chore: upload tavily search class

[radugheo]

This PR is linked to this issue.
It updates the samples to use the new TavilySearch class instead of the deprecated TavilySearchResults and also updates the uipath-langchain dependency.

[Copilot]

Pull Request Overview

This PR migrates from the deprecated TavilySearchResults class to the new TavilySearch class across sample projects and updates dependencies accordingly.

Key changes:

• Replace deprecated TavilySearchResults import with TavilySearch from langchain_tavily
• Update dependency specifications to use minimum version constraints and add langchain-tavily package
• Remove unused optional dependencies section from root pyproject.toml

Reviewed Changes

Copilot reviewed 5 out of 8 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
samples/multi-agent-planner-researcher-coder-distributed/src/multi-agent-distributed/researcher.py	Updates import and instantiation to use TavilySearch instead of deprecated TavilySearchResults
samples/multi-agent-planner-researcher-coder-distributed/pyproject.toml	Adds langchain-tavily dependency and changes uipath-langchain to minimum version constraint
samples/RAG-quiz-generator/src/agents/researcher-RAG-agent.py	Updates import and instantiation to use TavilySearch instead of deprecated TavilySearchResults
samples/RAG-quiz-generator/pyproject.toml	Adds langchain-tavily dependency and changes uipath-langchain to minimum version constraint
pyproject.toml	Removes unused optional dependencies section for langchain

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[radu-mocanu]

uipath-langchain dependency updates were addressed as part of this PR #159.
the current branch should be rebased on top of this

[radu-mocanu]

let's uncommit this file, please

[radu-mocanu]

this also needs to be uncommited