refactor(state_keeper): switch from milliseconds to seconds in time u…

…tils

Resolves SMA-1206

- Renamed millis_since_epoch() to seconds_since_epoch()
- Changed time representation from milliseconds to seconds
- Updated millis_since() to work with seconds while maintaining its interface
- Improved type safety by using u64 instead of u128

core/node/state_keeper/src/utils.rs

@@ -6,14 +6,13 @@ pub(super) fn is_canceled(stop_receiver: &watch::Receiver<bool>) -> bool {
     *stop_receiver.borrow()
 }
 
-// TODO (SMA-1206): use seconds instead of milliseconds.
-pub(super) fn millis_since_epoch() -> u128 {
+pub(super) fn seconds_since_epoch() -> u64 {
     SystemTime::now()
         .duration_since(UNIX_EPOCH)
         .expect("Incorrect system time")
-        .as_millis()
+        .as_secs()
 }
 
 pub(super) fn millis_since(since: u64) -> u64 {
-    (millis_since_epoch() - since as u128 * 1000) as u64
+    (seconds_since_epoch() - since) * 1000
 }