feat(widget-sessions): improve session filtering logic

- Refactored session filtering logic to handle nested filters properly.
- Enhanced `fetchSessions` to ensure null checks and avoid errors.
- Updated `loadData` to handle `USER_PATH` and `HEATMAP` metric types.
- Improved UI consistency by adjusting spacing and formatting.
- Replaced redundant code with cleaner, more maintainable patterns.

This change improves the reliability and readability of the session
filtering and loading logic in the WidgetSessions component.

frontend/app/components/Dashboard/components/WidgetSessions/WidgetSessions.tsx

@@ -66,8 +66,7 @@ function WidgetSessions(props: Props) {
 
     const fetchSessions = (metricId: any, filter: any) => {
         if (!isMounted()) return;
-    setLoading(true);
-    delete filter.eventsOrderSupport;
+
         if (widget.metricType === FUNNEL) {
             if (filter.series[0].filter.filters.length === 0) {
                 setLoading(false);
@@ -75,8 +74,28 @@ function WidgetSessions(props: Props) {
             }
         }
 
+
+        setLoading(true);
+        const filterCopy = {...filter};
+        delete filterCopy.eventsOrderSupport;
+
+        try {
+            // Handle filters properly with null checks
+            if (filterCopy.filters && filterCopy.filters.length > 0) {
+                // Ensure the nested path exists before pushing
+                if (filterCopy.series?.[0]?.filter) {
+                    if (!filterCopy.series[0].filter.filters) {
+                        filterCopy.series[0].filter.filters = [];
+                    }
+                    filterCopy.series[0].filter.filters.push(...filterCopy.filters);
+                }
+                filterCopy.filters = [];
+            }
+        } catch (e) {
+            // do nothing
+        }
         widget
-      .fetchSessions(metricId, filter)
+            .fetchSessions(metricId, filterCopy)
             .then((res: any) => {
                 setData(res);
                 if (metricStore.drillDown) {