Merge pull request pkp#10803 from bozana/10790

pkp#10790 do not redirect in PKPPageRouter in case of install and help page, remove header and sidebar installation page

classes/core/PKPPageRouter.php

@@ -29,7 +29,7 @@
 class PKPPageRouter extends PKPRouter
 {
     /** @var array pages that don't need an installed system to be displayed */
-    public $_installationPages = ['install', 'help', 'header', 'sidebar'];
+    public $_installationPages = ['install', 'help'];
 
     public const ROUTER_DEFAULT_PAGE = './pages/index/index.php';
     public const ROUTER_DEFAULT_OP = 'index';
@@ -169,9 +169,6 @@ public function route(PKPRequest $request): void
             // the system is not yet installed. Redirect to
             // the installation page.
             $request->redirect(Application::SITE_CONTEXT_PATH, 'install');
-        } elseif (Application::isInstalled() && in_array($page, $this->getInstallationPages())) {
-            // Redirect to the index page
-            $request->redirect(Application::SITE_CONTEXT_PATH, 'index');
         }
 
         // Redirect requests from logged-out users to a context which is not