[Chef] Fix compile -a doesn't work on ESP32 (#26095)

* [Chef] Fix compile -a doesn't work on ESP32

with `chef.py --automated_test_stamp` we can assign timestamp as
software version string when compiling chef sample device. However, this
failed on ESP32. On ESP32, I found that it uses PROJECT_VER to overwrite
CHIP_DEVICE_CONFIG_DEVICE_SOFTWARE_VERSION_STRING, so I set it in the esp32's
CMakeLists.txt

* chef.py set default sw_ver_string from "v1.0" to""

* Add comment in examples/chef/esp32/CMakeLists.txt

examples/chef/chef.py

@@ -615,10 +615,11 @@ def main() -> int:
                     f"\"{truncated_sw_ver_string}\" due to 64 bytes limitation")
                 sw_ver_string = truncated_sw_ver_string
 
-        flush_print("Building...")
-
+        flush_print(f"Software Version String: \"{sw_ver_string}\"")
         flush_print(
             f"Product ID 0x{options.pid:02X} / Vendor ID 0x{options.vid:02X}")
+        flush_print("Building...")
+
         shell.run_cmd(f"cd {_CHEF_SCRIPT_PATH}")
 
         if (options.build_target == "esp32") or (options.build_target == "nrfconnect") or (options.build_target == "ameba"):

examples/chef/esp32/CMakeLists.txt

@@ -46,8 +46,10 @@ idf_build_set_property(COMPILE_OPTIONS "-DCHIP_DEVICE_CONFIG_DEVICE_PRODUCT_ID=$
 if(NOT ${CONFIG_DEVICE_PRODUCT_NAME} STREQUAL "")
     idf_build_set_property(COMPILE_OPTIONS "-DCHIP_DEVICE_CONFIG_DEVICE_PRODUCT_NAME=\"${CONFIG_DEVICE_PRODUCT_NAME}\"" APPEND)
 endif()
+# Forwarding the customized software version string to the ESP32 firmware image
 if(NOT ${CHIP_DEVICE_CONFIG_DEVICE_SOFTWARE_VERSION_STRING} STREQUAL "")
     idf_build_set_property(COMPILE_OPTIONS "-DCHIP_DEVICE_CONFIG_DEVICE_SOFTWARE_VERSION_STRING=\"${CHIP_DEVICE_CONFIG_DEVICE_SOFTWARE_VERSION_STRING}\"" APPEND)
+    set(PROJECT_VER ${CHIP_DEVICE_CONFIG_DEVICE_SOFTWARE_VERSION_STRING})
 endif()
 idf_build_set_property(COMPILE_OPTIONS "-DCHIP_PLATFORM_ESP32=1" APPEND)