community, langchain, infra: store extended test deps outside of poetry (#18995)

poetry can't reliably handle resolving the number of optional "extended
test" dependencies we have. If we instead just rely on pip to install
extended test deps in CI, this isn't an issue.

libs/experimental/extended_requirements.txt

@@ -0,0 +1,8 @@
+presidio-anonymizer
+presidio-analyzer
+faker
+vowpal-wabbit-next
+sentence-transformers
+jinja2
+pandas
+tabulate

libs/experimental/pyproject.toml

@@ -12,14 +12,6 @@ repository = "https://github.com/langchain-ai/langchain"
 python = ">=3.8.1,<4.0"
 langchain-core = "^0.1.31"
 langchain = "^0.1.12"
-presidio-anonymizer = {version = "^2.2.352", optional = true}
-presidio-analyzer = {version = "^2.2.352", optional = true}
-faker = {version = "^19.3.1", optional = true}
-vowpal-wabbit-next = {version = "0.6.0", optional = true}
-sentence-transformers = {version = "^2", optional = true}
-jinja2 = {version = "^3", optional = true}
-pandas = { version = "^2.0.1", optional = true }
-tabulate = {version = "^0.9.0", optional = true}
 
 [tool.poetry.group.lint]
 optional = true
@@ -70,21 +62,6 @@ langchain = {path = "../langchain", develop = true}
 langchain-core = {path = "../core", develop = true}
 langchain-community = {path = "../community", develop = true}
 
-# An extra used to be able to add extended testing.
-# Please use new-line on formatting to make it easier to add new packages without
-# merge-conflicts
-[tool.poetry.extras]
-extended_testing = [
- "presidio-anonymizer",
- "presidio-analyzer",
- "faker",
- "vowpal-wabbit-next",
- "sentence-transformers",
- "jinja2",
- "pandas",
- "tabulate",
-]
-
 [tool.ruff.lint]
 select = [
   "E",  # pycodestyle