Added reusable wrapper and implemented reusable wrapper for logfire (and other ops providers)

[brenkao]

• Refactored logfire, weave, and langfuse to share ops_utils.
• Updated langfuse to use observe to get pretty nesting
• Enables functionality described in Add a callback to easily track data #238 with documentation.
• Updated logfire anthropic to use instrument_anthropic

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (34b0c2a) to head (f9aa1ad).
Report is 5 commits behind head on dev.

❗ Current head f9aa1ad differs from pull request most recent head 062dab7

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Additional details and impacted files

@@            Coverage Diff            @@
##               dev      #244   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          126       129    +3     
  Lines         6384      6360   -24     
=========================================
- Hits          6384      6360   -24     

Flag	Coverage Δ
tests	100.00% <100.00%> (ø)

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