CI: enable example builds for C3

Enables building C3 examples in CI.

Fixes related warnings/errors and disables examples that cannot run.

examples/system/console/components/cmd_system/cmd_system.c

@@ -233,7 +233,11 @@ static int deep_sleep(int argc, char **argv)
         ESP_LOGE(TAG, "GPIO wakeup from deep sleep currently unsupported on ESP32-C3");
     }
 #endif // SOC_PM_SUPPORT_EXT_WAKEUP
+
+#if CONFIG_IDF_TARGET_ESP32
     rtc_gpio_isolate(GPIO_NUM_12);
+#endif //CONFIG_IDF_TARGET_ESP32
+
     esp_deep_sleep_start();
 }