Fix MinecraftLaunch failing in the case of a package-private main class on Java 8 (#3932)

I don't know of any mod loaders where this is the case, but better be safe than sorry

packages/app-lib/java/src/main/java/com/modrinth/theseus/MinecraftLaunch.java

@@ -123,6 +123,7 @@ public final class MinecraftLaunch {
             setAccessible0.setAccessible(true);
             setAccessible0.invoke(object, true);
         } catch (NoSuchMethodException e) {
+            object.setAccessible(true);
         }
         return object;
     }