DB: remove TZ info from get_{observation,timeseries}_history dates

Remove timezone data from `t1` and `t2` dates in `get_observation_history` and `get_timeseries_history`.

This fixes `TypeError: can't compare offset-naive and offset-aware datetimes` present in API when request to `/entity/{entity}/{eid}` was made with `date_from` and `date_to` parameters containing timestamps like 1689745000000.

dp3/database/database.py

@@ -510,8 +510,8 @@ def get_observation_history(
         Returns:
             list of dicts (reduced datapoints)
         """
-        t1 = datetime.fromtimestamp(0) if t1 is None else t1
-        t2 = datetime.now() if t2 is None else t2
+        t1 = datetime.fromtimestamp(0) if t1 is None else t1.replace(tzinfo=None)
+        t2 = datetime.now() if t2 is None else t2.replace(tzinfo=None)
 
         # Get attribute history
         mr = self.get_master_record(etype, eid)
@@ -565,8 +565,8 @@ def get_timeseries_history(
         Returns:
              list of dicts (reduced datapoints) - each represents just one point at time
         """
-        t1 = datetime.fromtimestamp(0) if t1 is None else t1
-        t2 = datetime.now() if t2 is None else t2
+        t1 = datetime.fromtimestamp(0) if t1 is None else t1.replace(tzinfo=None)
+        t2 = datetime.now() if t2 is None else t2.replace(tzinfo=None)
 
         attr_history = self.get_observation_history(etype, attr_name, eid, t1, t2, sort)
         if not attr_history: