Release langchain-core==0.2.9

Changes since langchain-core==0.2.8

core[patch]: Pin pydantic in py3.12.4 (#23130)
docs: Fix URL formatting in deprecation warnings (#23075)
core[minor]: Support multiple keys in get_from_dict_or_env (#23086)
core[patch]: Release 0.2.9 (#23091)
core[patch]: Document BaseStore (#23082)
core[patch],community[patch],langchain[patch]: tenacity dependency to version >=8.1.0,<8.4.0 (#22973)
Include "no escape" and "inverted section" mustache vars in Prompt.input_variables and Prompt.input_schema (#22981)
core[minor]: message transformer utils (#22752)