CI: seperate esp32s2 into different job

skip esp32s in build_all.py script

tools/build_all.py

@@ -57,8 +57,8 @@ def skip_example(example, board):
     with open(board_mk) as mk:
         mk_contents = mk.read()
 
-        # Skip ESP32-S2 board if example is not FreeRTOS one
-        if 'freertos' not in example and 'CROSS_COMPILE = xtensa-esp32s2-elf-' in mk_contents:
+        # Skip all ESP32-S2 board for CI
+        if 'CROSS_COMPILE = xtensa-esp32s2-elf-' in mk_contents:
             return 1
 
         # Skip if CFG_TUSB_MCU in board.mk to match skip file