main: Slightly refactor NCA entry installation in InstallNCA (#7181)

* main: Slightly refactor NCA entry installation in InstallNCA

Co-authored-by: Ameer J <52414509+ameerj@users.noreply.github.com>

src/yuzu/main.cpp

@@ -2381,15 +2381,13 @@ InstallResult GMainWindow::InstallNCA(const QString& filename) {
                  static_cast<size_t>(FileSys::TitleType::FirmwarePackageB);
     }
 
-    FileSys::InstallResult res;
-    if (index >= static_cast<s32>(FileSys::TitleType::Application)) {
-        res = system.GetFileSystemController().GetUserNANDContents()->InstallEntry(
-            *nca, static_cast<FileSys::TitleType>(index), true, qt_raw_copy);
-    } else {
-        res = system.GetFileSystemController().GetSystemNANDContents()->InstallEntry(
-            *nca, static_cast<FileSys::TitleType>(index), true, qt_raw_copy);
-    }
+    const bool is_application = index >= static_cast<s32>(FileSys::TitleType::Application);
+    const auto& fs_controller = system.GetFileSystemController();
+    auto* registered_cache = is_application ? fs_controller.GetUserNANDContents()
+                                            : fs_controller.GetSystemNANDContents();
 
+    const auto res = registered_cache->InstallEntry(*nca, static_cast<FileSys::TitleType>(index),
+                                                    true, qt_raw_copy);
     if (res == FileSys::InstallResult::Success) {
         return InstallResult::Success;
     } else if (res == FileSys::InstallResult::OverwriteExisting) {