Graph: Revert bar centering to fix tooltip issue (#26876)

public/app/plugins/panel/graph/graph.ts

@@ -516,7 +516,6 @@ class GraphElement {
       }
       default: {
         options.series.bars.barWidth = this.getMinTimeStepOfSeries(this.data) / 1.5;
-        options.series.bars.align = 'center';
         this.addTimeAxis(options);
         break;
       }