Update BubbleChartDataset styling for better visuals

Changed BackgroundColor to use ToRgbaString(0.5) for transparency
and reduced BorderWidth from 3 to 1 for a cleaner appearance.

NOTE: This commit message is auto-generated using GitHub Copilot.

Author: gvreddy04

BlazorExpress.ChartJS.Demo.RCL/Pages/Demos/BubbleChart/BubbleChart_Demo_01_Examples.razor

@@ -114,9 +114,9 @@
         {
             Label = $"Product {datasetsCount}",
             Data = GetRandomData(),
-            BackgroundColor = new List<string> { c.ToRgbString() },
+            BackgroundColor = new List<string> { c.ToRgbaString(0.5) },
             BorderColor = new List<string> { c.ToRgbString() },
-            BorderWidth = 3,
+            BorderWidth = 1,
         };
     }