fix(PdfViewer): no render when url is empty (#6522)

Author: ArgoZhang

src/BootstrapBlazor.Server/BootstrapBlazor.Server.csproj

@@ -61,7 +61,7 @@
     <PackageReference Include="BootstrapBlazor.OfficeViewer" Version="9.0.0" />
     <PackageReference Include="BootstrapBlazor.OnScreenKeyboard" Version="9.0.1" />
     <PackageReference Include="BootstrapBlazor.PdfReader" Version="9.0.1" />
-    <PackageReference Include="BootstrapBlazor.PdfViewer" Version="9.0.5" />
+    <PackageReference Include="BootstrapBlazor.PdfViewer" Version="9.0.6" />
     <PackageReference Include="BootstrapBlazor.Player" Version="9.0.1" />
     <PackageReference Include="BootstrapBlazor.RDKit" Version="9.0.2" />
     <PackageReference Include="BootstrapBlazor.SignaturePad" Version="9.0.1" />