micropython: Don't set mode to app on launch

py,st3m does it on its own. This lets the bootsplash animation
run for longer and fixes the bootsplash not showing up at all
on soft reboot.

components/micropython/vendor/ports/esp32/main.c

@@ -132,8 +132,6 @@ soft_reset:
     machine_i2s_init0();
     #endif
 
-    st3m_mode_set(st3m_mode_kind_app, NULL);
-
     // run boot-up scripts
     pyexec_frozen_module("_boot.py");
     pyexec_file_if_exists("boot.py");