feat: Rename Firebeetle ESP32 board definition (espressif#9250)

Author: matthias-bs

Diff for: boards.txt

@@ -9996,7 +9996,7 @@ firebeetle32.build.target=esp32
 firebeetle32.build.mcu=esp32
 firebeetle32.build.core=esp32
 firebeetle32.build.variant=firebeetle32
-firebeetle32.build.board=ESP32_DEV
+firebeetle32.build.board=DFROBOT_FIREBEETLE_ESP32
 
 firebeetle32.build.f_cpu=240000000L
 firebeetle32.build.flash_mode=dio