[feature request] support LlamaIndex instrumentation tags

[mikeldking]

LlamaIndex released an update to instrumentation

Basically, users can add arbitrary tags to their spans/events
from llama_index.core.instrumentation.dispatcher import instrument_tags

with instrument_tags({"user_id": 1234}):
agent.chat("Hello!")
Any events/spans emitted under the with block will have a .tags attribute with the provided tags attached

Instrumentation should parse this part of the span and attach it as metadata's