fix: anthropic temperature parameter not respecting value 0 (#2190)

Co-authored-by: Marcus Schiesser <marcus.schiesser@googlemail.com>

.changeset/light-spiders-pump.md

@@ -0,0 +1,5 @@
+---
+"@llamaindex/anthropic": patch
+---
+
+fix: anthropic temperature parameter not respecting value 0

packages/providers/anthropic/src/llm.ts

@@ -179,7 +179,7 @@ export class Anthropic extends ToolCallLLM<
   constructor(init?: Partial<Anthropic>) {
     super();
     this.model = init?.model ?? "claude-3-opus";
-    this.temperature = init?.temperature ?? 1; // default in anthropic is 1
+    this.temperature = init?.temperature != null ? init.temperature : 1; // default in anthropic is 1
     this.topP = init?.topP;
     this.maxTokens = init?.maxTokens ?? undefined;