Change LaunchTask to only accept MinecraftInstance

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

launcher/minecraft/launch/VerifyJavaInstall.cpp

@@ -46,7 +46,7 @@
 
 void VerifyJavaInstall::executeTask()
 {
-    auto instance = std::dynamic_pointer_cast<MinecraftInstance>(m_parent->instance());
+    auto instance = m_parent->instance();
     auto packProfile = instance->getPackProfile();
     auto settings = instance->settings();
     auto storedVersion = settings->get("JavaVersion").toString();