feat(whitelisting): Explicitly tell which app is blocked to user

Signed-off-by: Louis Chmn <louis@chmn.me>

Author: artonge

lib/AppWhitelist.php

@@ -77,10 +77,13 @@ public function isUrlAllowed(IUser $user, string|false $url): bool {
 	}
 
 	public function verifyAccess(IUser $user, IRequest $request): void {
-		if (!$this->isUrlAllowed($user, $request->getPathInfo())) {
+		$url = $request->getPathInfo();
+		$app = $this->getRequestedApp($url);
+
+		if (!$this->isUrlAllowed($user, $url)) {
 			header('HTTP/1.0 403 Forbidden');
 			Template::printErrorPage($this->l10n->t(
-				'Access to this resource is forbidden for guests.'
+				"Access to this resource ($app) is forbidden for guests."
 			));
 			exit;
 		}