Fix(metrics) - Add exit hook for cleanup in Optl sdk (#8930)

Co-authored-by: Shi Shu <shii@google.com>

packages/core/src/telemetry/sdk.ts

@@ -198,6 +198,9 @@ export function initializeTelemetry(config: Config): void {
   process.on('SIGINT', () => {
     shutdownTelemetry(config);
   });
+  process.on('exit', () => {
+    shutdownTelemetry(config);
+  });
 }
 
 export async function shutdownTelemetry(config: Config): Promise<void> {