Update defaults (#7223)

CHANGELOG.md

docs/core_modules/data_modules/node_parsers/usage_pattern.md

docs/core_modules/model_modules/embeddings/usage_pattern.md

docs/core_modules/model_modules/llms/modules.md

docs/core_modules/model_modules/llms/root.md

...core_modules/query_modules/node_postprocessors/modules.md

docs/core_modules/supporting_modules/service_context.md

docs/end_to_end_tutorials/usage_pattern.md

docs/examples/embeddings/Langchain.ipynb

docs/examples/index_structs/doc_summary/DocSummary.ipynb

.../examples/index_structs/struct_indices/SQLIndexDemo.ipynb

docs/examples/llm/llama_2_llama_cpp.ipynb

.../examples/metadata_extraction/MetadataExtractionSEC.ipynb

...examples/node_postprocessor/MetadataReplacementDemo.ipynb

docs/examples/query_engine/json_query_engine.ipynb

docs/getting_started/installation.md

experimental/splitter_playground/app.py

llama_index/bridge/langchain.py

llama_index/callbacks/wandb_callback.py

llama_index/composability/joint_qa_summary.py