[mt][browser] Prevent SignalRClientTests fail with "PlaywrightException: Target closed" (#99537)

* Wait on network idle (longer time) instead of just load the DOM.

* Revert most of CI seedup

* Add fixed delay.

* Trigger the test-related actiont after the app is rendered

* Fix bool arg

* Update src/mono/wasm/testassets/BlazorHostedApp/BlazorHosted.Client/Pages/Chat.razor

Co-authored-by: Marek Fišera <[email protected]>

* Revert WBT runs limitation.

---------

Co-authored-by: Marek Fišera <[email protected]>

Author: ilonatommy

src/mono/wasm/testassets/BlazorHostedApp/BlazorHosted.Client/Pages/Chat.razor

@@ -27,9 +27,11 @@
     private List<string> chatMessages = new List<string>();
     private string wrongQueryError = "Query string with parameters 'message' and 'transport' are required";
 
-    protected override void OnInitialized()
+    protected override void OnAfterRender(bool firstRender)
     {
-        Helper.TestOutputWriteLine($"OnInitialized on CurrentManagedThreadId={Environment.CurrentManagedThreadId}");
+        base.OnAfterRender(firstRender);
+
+        Helper.TestOutputWriteLine($"OnAfterRender on CurrentManagedThreadId={Environment.CurrentManagedThreadId}");
         GetQueryParameters();
     }