Fix "Cannot read properties of null" in cli/telemetry (#8443)

Co-authored-by: Erika <3019731+Princesseuh@users.noreply.github.com>

Author: mhdcodes

.changeset/strong-colts-hang.md

@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Fix "Cannot read properties of null" error in CLI code

packages/astro/src/cli/telemetry/index.ts

@@ -9,7 +9,7 @@ interface TelemetryOptions {
 }
 
 export async function notify() {
-	const packageManager = (await whichPm(process.cwd())).name ?? 'npm';
+	const packageManager = (await whichPm(process.cwd()))?.name ?? 'npm';
 	await telemetry.notify(() => {
 		console.log(msg.telemetryNotice(packageManager) + '\n');
 		return true;