fix: handle toll call with no input

[GabrielVasilescu04]

Description

Fixes #333. Also remove content_part_sequence from the content part chunk events since it's no longer present on the contracts

Development Package

• Add this package as a dependency in your pyproject.toml:

[project]
dependencies = [
  # Exact version:
  "uipath-langchain==0.1.32.dev1003581567",

  # Any version from PR
  "uipath-langchain>=0.1.32.dev1003580000,<0.1.32.dev1003590000"
]

[[tool.uv.index]]
name = "testpypi"
url = "https://test.pypi.org/simple/"
publish-url = "https://test.pypi.org/legacy/"
explicit = true

[tool.uv.sources]
uipath-langchain = { index = "testpypi" }