[App] Python; Drop unused cast to volatile T.

The warning is issued by MSVC:
Compiler Warning (level 3) C4197.
type' : top-level volatile in cast is ignored

Applications/CLI/ogs_embedded_python.cpp

@@ -28,7 +28,7 @@ PYBIND11_EMBEDDED_MODULE(OpenGeoSys, m)
 template <typename T>
 void mark_used(T p)
 {
-    volatile T vp = (volatile T)p;
+    volatile T vp = p;
     vp = vp;
 }