Optimize handling of alert panel names and panel alerts

This commit refactors how alert panel names and panel alerts are handled. For the alert panel names, allocation has been optimized by initializing the map with the size of the alerts array. Checking for panels with alerts has also been simplified to just check the length of alerts rather than checking for null and length simultaneously.

dashboards.go

@@ -125,7 +125,7 @@ func (client *Client) UpsertDashboard(ctx context.Context, folder *Folder, build
 		return nil, err
 	}
 
-	alertPanelNames := make(map[string]struct{})
+	alertPanelNames := make(map[string]struct{}, len(alerts))
 	for _, al := range alerts {
 		alertPanelNames[al.PanelName] = struct{}{}
 	}

row/row.go

@@ -58,7 +58,7 @@ func WithGraph(title string, options ...graph.Option) Option {
 
 		row.builder.Add(panel.Builder)
 
-		if panel.Alerts == nil || len(panel.Alerts) == 0 {
+		if len(panel.Alerts) == 0 {
 			return nil
 		}
 
@@ -84,7 +84,7 @@ func WithTimeSeries(title string, options ...timeseries.Option) Option {
 
 		row.builder.Add(panel.Builder)
 
-		if panel.Alerts == nil || len(panel.Alerts) == 0 {
+		if len(panel.Alerts) == 0 {
 			return nil
 		}