anthropic dependency vs LiteLLMProvider usage

[yashh152004]

Problem

The current node execution path still assumes the presence of the
Anthropic client, even when LiteLLM is configured as the provider.
This causes unnecessary coupling and failures when Anthropic is not installed.

Expected behavior

Nodes should rely only on the configured LLM provider abstraction
(e.g. LiteLLMProvider) without importing or requiring Anthropic.

Scope

• Remove Anthropic-specific usage from node execution
• Keep changes minimal and focused
• No setup, Windows, or documentation changes

Notes

A previous Anthropic-related issue appears to be resolved, but this
specific dependency still exists in the code path.

[github-actions]

Found a possible duplicate of #1135: Architecture: Remove Hardcoded Anthropic Dependency

This issue describes the same architectural problem - hardcoded Anthropic SDK dependency in NodeResult.to_summary() that violates the provider-agnostic design. Issue #1135 is the main tracking issue for this problem and has more context and discussion. If you disagree that this is a duplicate, please react with a thumbs-down.