Merge branch 'fix/openthread_rcp_uart_senddone_on_fail_v6.0' into 'release/v6.0'

fix(openthread): avoid HDLC TX stall on fd write failure (v6.0)

See merge request espressif/esp-idf!49071

components/openthread/src/port/esp_openthread_uart.c

@@ -60,12 +60,10 @@ otError otPlatUartSend(const uint8_t *buf, uint16_t buf_length)
     usb_serial_jtag_ll_txfifo_flush();
 #endif
 
+    otPlatUartSendDone();
     if (rval != (int)buf_length) {
         return OT_ERROR_FAILED;
     }
-
-    otPlatUartSendDone();
-
     return OT_ERROR_NONE;
 }
 #endif