refactor: Updated AIM instrumentation

[bizob2828]

Description

This PR addresses a few items that were codified into the specification that we were missing:

• remove capturing api key
• update tracking metric to start with Supportability/Nodejs/ML
• include any custom attributes that start with llm. except llm.conversation_id as attributes on all Llm Events.

Related Issues

Closes #2007

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (4daedc0) 97.10% compared to head (ab0c96d) 97.13%.
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2015      +/-   ##
==========================================
+ Coverage   97.10%   97.13%   +0.02%     
==========================================
  Files         239      239              
  Lines       41017    41050      +33     
==========================================
+ Hits        39831    39875      +44     
+ Misses       1186     1175      -11     

Flag	Coverage Δ
integration-tests-16.x	78.78% <38.88%> (+0.04%)	⬆️
integration-tests-18.x	78.78% <38.88%> (+0.05%)	⬆️
integration-tests-20.x	78.78% <38.88%> (+0.05%)	⬆️
unit-tests-16.x	91.16% <100.00%> (+0.08%)	⬆️
unit-tests-18.x	91.05% <100.00%> (+0.08%)	⬆️
unit-tests-20.x	91.05% <100.00%> (+0.08%)	⬆️
versioned-tests-16.x	74.98% <77.77%> (+0.01%)	⬆️
versioned-tests-18.x	75.00% <77.77%> (+0.01%)	⬆️
versioned-tests-20.x	75.01% <77.77%> (+0.01%)	⬆️

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[jsumners-nr]

Looks good to me.