As reported by @gruberaaron , work to improve the 1200bps reset for
esptool caused all runs of device-install.bat to use 1200bps as
the baud rate.
This change removes the general SET "ESPTOOL_BAUD=1200" that was causing
the issues and places the baud settings for reset mode inside the conditional.
Fixes https://github.com/meshtastic/firmware/issues/7172