fix(chart): missing BootstrapBlazor class (#593)

* fix(chart):修复初始化时产生的未定义错误

* chore: bump version 9.0.3

---------

Co-authored-by: Argo Zhang <argo@live.ca>

Author: kimdiego2098

src/components/BootstrapBlazor.Chart/BootstrapBlazor.Chart.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Razor">
 
   <PropertyGroup>
-    <Version>9.0.2</Version>
+    <Version>9.0.3</Version>
   </PropertyGroup>
 
   <PropertyGroup>

src/components/BootstrapBlazor.Chart/Components/Chart/Chart.razor.js

@@ -6,6 +6,10 @@ import EventHandler from "../../../BootstrapBlazor/modules/event-handler.js"
 
 Chart.register(ChartDataLabels);
 
+if (window.BootstrapBlazor === void 0) {
+    window.BootstrapBlazor = {};
+}
+
 if (window.BootstrapBlazor.Chart === void 0) {
     const elementMap = new Map();
     window.BootstrapBlazor.Chart = new class {