refactor: use helper function in both places for agent extraction

Previously, both transformTelemetryMetadata and transformAiSdkSpanNames
had their own logic to extract agent name from ai.telemetry.metadata.agent
attributes. This consolidates both to use the shared getAgentNameFromAttributes
helper, eliminating code duplication.

Addresses PR feedback about existing agent extraction code.

Author: galkleinman

packages/traceloop-sdk/src/lib/tracing/ai-sdk-transformations.ts

@@ -433,7 +433,8 @@ const transformTelemetryMetadata = (
 ): void => {
   const metadataAttributes: Record<string, string> = {};
   const keysToDelete: string[] = [];
-  let agentName: string | null = null;
+  // Use the helper function to extract agent name
+  const agentName = getAgentNameFromAttributes(attributes);
 
   // Find all ai.telemetry.metadata.* attributes
   for (const [key, value] of Object.entries(attributes)) {
@@ -448,11 +449,6 @@ const transformTelemetryMetadata = (
         const stringValue = typeof value === "string" ? value : String(value);
         metadataAttributes[metadataKey] = stringValue;
 
-        // Check for agent-specific metadata
-        if (metadataKey === "agent") {
-          agentName = stringValue;
-        }
-
         // Also set as traceloop association property attribute
         attributes[
           `${SpanAttributes.TRACELOOP_ASSOCIATION_PROPERTIES}.${metadataKey}`