Revert "remove sleep on launch (#28236)"

This reverts commit fddd299a3a598a948776e73f1a45fe4b0d69db7f.

old-commit-hash: 309eccad3a

launch_chffrplus.sh

@@ -9,6 +9,11 @@ source "$BASEDIR/launch_env.sh"
 DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
 
 function agnos_init {
+  # wait longer for weston to come up
+  if [ -f "$BASEDIR/prebuilt" ]; then
+    sleep 3
+  fi
+
   # TODO: move this to agnos
   sudo rm -f /data/etc/NetworkManager/system-connections/*.nmmeta