chore: use hitl methods from core

[radu-mocanu]

New test-core-dev-version label:

• add this label to test the changes against a custom uipath dev version
• the dev version must be specified in PR's title like so: chore: extract to core (validate with uipath version 2.0.65.dev1004030443)

Github actions updates:

• skip normal tests and lint when test-core-dev-version label si used
• added test-custom-version.yml and lint-custom-version.yml to target a specific uipath version from testpypi
• when both build:dev and test-core-dev-version labels are used, publish a dev uipath-langchain version relying on the uipath dev version

Runtime updates:

• use HitlReader and HitlProcessor from core
• special handling for default escalation scenarios (cast output from bool to str)
• only pass str value (event prefix) for api triggers

Development Package

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

[project]
dependencies = [
  # Exact version:
  "uipath-llamaindex==0.0.25.dev1000320095",

  # Any version from PR
  "uipath-llamaindex>=0.0.25.dev1000320000,<0.0.25.dev1000330000"
]

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

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