more stack for json, more json for mqtt

rust/src/plant_hal.rs

@@ -17,7 +17,7 @@ use esp_idf_svc::mqtt::client::{EspMqttClient, LwtConfiguration, MqttClientConfi
 use esp_idf_svc::nvs::EspDefaultNvsPartition;
 use esp_idf_svc::wifi::config::{ScanConfig, ScanType};
 use esp_idf_svc::wifi::EspWifi;
-use measurements::{Frequency, Temperature};
+use measurements::Temperature;
 use plant_ctrl2::sipo::ShiftRegister40;
 
 use anyhow::anyhow;