Add `enableTruncation` option to Anthropic AI integration

[andreiborza]

Add an enableTruncation option to the Anthropic AI integration that controls whether input messages are truncated before being stored as span attributes. Should default to true to preserve current behavior.

[linear-code]

JS-2056

[github-actions]

A PR closing this issue has just been released 🚀

This issue was referenced by PR #20181, which was included in the 10.49.0 release.