chore(common): update server instructions to avoid prerendering issue

Author: marin-bratanov

getting-started/server-blazor.md

@@ -53,6 +53,8 @@ To use Blazor server-side, you need to use the `Blazor App` type of project with
 
         <link rel="stylesheet" href="https://unpkg.com/@@progress/kendo-theme-default@@latest/dist/all.css" />
 
+1. Remove the contents of the `<app></app>` element (see [this issue](https://feedback.telerik.com/blazor/1425656-using-renderstaticcomponentasync-breaks-telerik-components)).
+        
 1. @[template](/_contentTemplates/common/js-interop-file.md#add-js-interop-file-to-getting-started-server)
 
 1. Open the `~/Startup.cs` file in the and register the Telerik Blazor service:

getting-started/what-you-need.md

@@ -103,6 +103,10 @@ To allow working with detached popups (for example, dropdown lists, menus, grid
 @[template](/_contentTemplates/common/get-started.md#telerik-main-container-snippet)
 ````
 
+### Server-side Project Considerations
+
+Open the `~/Pages/_Host.cshtml` and remove the contents of the `<app></app>` element (see [this issue](https://feedback.telerik.com/blazor/1425656-using-renderstaticcomponentasync-breaks-telerik-components)).
+
 ### Client-side Project Considerations
 
 If you are using a **client-side Blazor** project,