hyprland/global_shortcuts: fix crash when protocol is not present

src/services/pipewire/module.md

@@ -0,0 +1,8 @@
+name = "Quickshell.Services.PipeWire"
+description = "Pipewire API"
+headers = [
+	"qml.hpp",
+	"link.hpp",
+	"node.hpp",
+]
+-----

src/wayland/hyprland/global_shortcuts/qml.cpp

@@ -25,7 +25,7 @@ void GlobalShortcut::onPostReload() {
 	}
 
 	auto* manager = GlobalShortcutManager::instance();
-	if (manager == nullptr) {
+	if (!manager->isActive()) {
 		qWarning() << "The active compositor does not support hyprland_global_shortcuts_v1.";
 		qWarning() << "GlobalShortcut will not work.";
 		return;