Give the zsh fork decline test more execution time (#33842)

## What changed

Increase the shell command timeout from 5 to 20 seconds in the app-server test
that verifies declining an intercepted subcommand marks its parent command as
declined.

GitOrigin-RevId: fbcc983c0ec0e2678858cffb70b905d763842677

codex-rs/app-server/tests/suite/v2/turn_start_zsh_fork.rs

@@ -497,7 +497,7 @@ async fn turn_start_shell_zsh_fork_subcommand_decline_marks_parent_declined_v2()
     let tool_call_arguments = serde_json::to_string(&serde_json::json!({
         "command": shell_command,
         "workdir": serde_json::Value::Null,
-        "timeout_ms": 5000
+        "timeout_ms": 20000
     }))?;
     let response = responses::sse(vec![
         responses::ev_response_created("resp-1"),