6296 fix charts and custom retention labels

Updates #6296

Squashed commit of the following:

commit e6a36f107b7bdd17fe4141b035fe5c1f6edd5c6c
Author: Ildar Kamalov <ik@adguard.com>
Date:   Fri Oct 13 17:42:41 2023 +0300

    changelog

commit 96f11f2090d2aff600f6dcd6ca601e25cd857530
Author: Ildar Kamalov <ik@adguard.com>
Date:   Fri Oct 13 16:01:27 2023 +0300

    changelog

commit 136fb14f61dcb2bdec3bc9b8943a05544752a606
Author: Ildar Kamalov <ik@adguard.com>
Date:   Fri Oct 13 15:20:14 2023 +0300

    ADG-7598 fix charts and custom retention labels

client/src/reducers/stats.js

@@ -1,6 +1,11 @@
 import { handleActions } from 'redux-actions';
 import { normalizeTopClients } from '../helpers/helpers';
-import { DAY, HOUR, STATS_INTERVALS_DAYS } from '../helpers/constants';
+import {
+    DAY,
+    HOUR,
+    STATS_INTERVALS_DAYS,
+    TIME_UNITS,
+} from '../helpers/constants';
 
 import * as actions from '../actions/stats';
 
@@ -18,6 +23,7 @@ const defaultStats = {
     numReplacedSafebrowsing: 0,
     numReplacedSafesearch: 0,
     avgProcessingTime: 0,
+    timeUnits: TIME_UNITS.HOURS,
 };
 
 const stats = handleActions(
@@ -60,6 +66,7 @@ const stats = handleActions(
                 avg_processing_time: avgProcessingTime,
                 top_upstreams_responses: topUpstreamsResponses,
                 top_upstrems_avg_time: topUpstreamsAvgTime,
+                time_units: timeUnits,
             } = payload;
 
             const newState = {
@@ -81,6 +88,7 @@ const stats = handleActions(
                 avgProcessingTime,
                 topUpstreamsResponses,
                 topUpstreamsAvgTime,
+                timeUnits,
             };
 
             return newState;