fix(picloud): use is_some_and in /auth/me test (clippy)

clippy::map_unwrap_or — drop the map().unwrap_or(false) for the
flatter is_some_and(Value::is_null).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/picloud/tests/api.rs

@@ -108,7 +108,7 @@ async fn auth_me_returns_principal_with_role_and_email(pool: PgPool) {
     assert_eq!(body["instance_role"], "owner");
     // Seeded admin has no email — must round-trip as null, not be missing.
     assert!(
-        body.get("email").map(Value::is_null).unwrap_or(false),
+        body.get("email").is_some_and(Value::is_null),
         "email should be present and null, got: {body}"
     );
     assert!(body["id"].as_str().is_some());