Replace pydantic_plugin in logfire.configure() with logfire.instrument_pydantic()

[alexmojaki]

Final part of logfire.configure() cleanup discussed here: https://pydantic.slack.com/archives/C05AF4A4WRM/p1725302678666539

Copilot summary

This pull request includes significant updates to the Pydantic plugin integration and related documentation. The primary changes involve simplifying the configuration process by introducing a new instrument_pydantic method and deprecating the old configuration method.

Documentation Updates:

• docs/integrations/pydantic.md: Updated instructions to use logfire.instrument_pydantic instead of the pydantic_plugin parameter in logfire.configure. Added notes to clarify the new usage. [1] [2] [3]
• docs/integrations/third-party/mirascope.md: Updated references to the Pydantic plugin to reflect the new configuration method. [1] [2]
• docs/why-logfire/pydantic.md: Updated example code to use the new instrument_pydantic method. [1] [2]

Codebase Simplification:

• logfire-api/logfire_api/__init__.py: Added instrument_pydantic method to the API. [1] [2]
• logfire/__init__.py: Added instrument_pydantic method to the default Logfire instance. [1] [2]

Deprecations and Removals:

• logfire/_internal/config.py: Deprecated the pydantic_plugin argument in logfire.configure and updated the internal configuration handling to use the new method. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]

Miscellaneous:

• logfire/_internal/config_params.py: Removed unused lru_cache import and related code. [1] [2]
• logfire/_internal/main.py: Updated imports to reflect changes in the configuration handling. [1] [2]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (a996819) to head (889b86a).
Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   100.00%   100.00%           
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  Files          131       131           
  Lines         9757      9782   +25     
  Branches      1286      1289    +3     
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+ Hits          9757      9782   +25     

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[Kludex]

How did you do the summary with copilot?

[alexmojaki]