freertos: don't create timer task if timer APIs are not used
freertos: don't create timer task if timer APIs are not used

Saves 2496 bytes of heap for the hello-world app on the ESP32,
and 4080 bytes of heap on the ESP32-S2 (due to IRAM savings).

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf