Add should_include_content() helper to extensions/otel/parser/base.py that
returns True in CE (no behaviour change) and respects ENTERPRISE_INCLUDE_CONTENT
in EE. Gate all content-bearing span attributes in LLM, retrieval, tool, and
default node parsers so that gen_ai.completion, gen_ai.prompt, retrieval.document,
tool call arguments/results, and node input/output values are suppressed when
ENTERPRISE_ENABLED=True and ENTERPRISE_INCLUDE_CONTENT=False.
