Don't use PTY in the display-only terminal (#39510)

This only affects `codex-acp` for now.

Not using the PTY in display-only terminals means they don't display the
login prompt (or spurious `%`s) at the end of terminal output
renderings.

Release Notes:

- N/A

crates/debugger_ui/src/session/running.rs

@@ -1232,7 +1232,6 @@ impl RunningState {
 
             terminal.read_with(cx, |terminal, _| {
                 terminal
-                    .pty_info
                     .pid()
                     .map(|pid| pid.as_u32())
                     .context("Terminal was spawned but PID was not available")