chore(layers): add pydantic-settings package to v3 Layer

[tkasuz]

Issue number: #5508

Summary

This PR adds pydantic-settings to simplify the migration from v2 to v3 for users building Lambda functions exclusively with Powertools layers, without the need for additional pip installations.

Changes

• Adds pydantic-settings as an optional package and includes it in all extra dependencies.

User experience

Before this change, users had to rewrite code using pydantic-settings with os to read environment variables, or stick with the v2 layer to use the BaseSettings class from Pydantic v1. With this update, however, users can now migrate smoothly from v2 to v3 without any changes to code that relies on pydantic-settings.

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• Meet tenets criteria
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented
• PR title follows conventional commit semantics

Is this a breaking change?

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[boring-cyborg]

Thanks a lot for your first contribution! Please check out our contributing guidelines and don't hesitate to ask whatever you need.
In the meantime, check out the #python channel on our Powertools for AWS Lambda Discord: Invite link

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.16%. Comparing base (6cfbbc9) to head (5e9362a).
Report is 1 commits behind head on develop.

Additional details and impacted files

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  Coverage    96.16%   96.16%           
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  Files          229      229           
  Lines        10810    10810           
  Branches      2007     2007           
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  Hits         10395    10395           
  Misses         327      327           
  Partials        88       88           

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[boring-cyborg]

Awesome work, congrats on your first merged pull request and thank you for helping improve everyone's experience!