Don't try to connect to X11/Wayland when headless (#15028)

Release Notes:

- remote development: Stopped logging every 16ms when connected to a
remote server with a badly configured X server.

crates/recent_projects/src/dev_servers.rs

@@ -1171,7 +1171,7 @@ pub async fn spawn_ssh_task(
         "-x".to_string(),
         "-c".to_string(),
         format!(
-            r#"~/.local/bin/zed -v >/dev/stderr || (curl -f https://zed.dev/install.sh || wget -qO- https://zed.dev/install.sh) | sh && ~/.local/bin/zed --dev-server-token {}"#,
+            r#"~/.local/bin/zed -v >/dev/stderr || (curl -f https://zed.dev/install.sh || wget -qO- https://zed.dev/install.sh) | sh && ZED_HEADLESS=1 ~/.local/bin/zed --dev-server-token {}"#,
             access_token
         ),
     ];