Remove duplicated include

Change-Id: I84dc37baac93f946bd66b6d709a43529d023dac6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/146381
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

animations/source/animcore/animcore.cxx

@@ -61,7 +61,6 @@
 #include <mutex>
 #include <vector>
 #include <algorithm>
-#include <mutex>
 
 namespace com::sun::star::uno { class XComponentContext; }
 namespace com::sun::star::beans { struct NamedValue; }