remove obsolete low battery check

watch-library/hardware/watch/watch.c

@@ -24,21 +24,14 @@
 
 #include "watch.h"
 
-bool battery_is_low = false;
-
 // receives interrupts from MCLK, OSC32KCTRL, OSCCTRL, PAC, PM, SUPC and TAL, whatever that is.
 void SYSTEM_Handler(void) {
     if (SUPC->INTFLAG.bit.BOD33DET) {
-        battery_is_low = true;
         SUPC->INTENCLR.bit.BOD33DET = 1;
         SUPC->INTFLAG.reg &= ~SUPC_INTFLAG_BOD33DET;
     }
 }
 
-bool watch_is_battery_low(void) {
-    return battery_is_low;
-}
-
 bool watch_is_buzzer_or_led_enabled(void){
     return hri_mclk_get_APBCMASK_TCC0_bit(MCLK);
 }