Update SheenBidi to 2.9.0

This fixes our problem with Valgrind reporting a jump based on an
uninitialized value; see https://github.com/Tehreer/SheenBidi/issues/19

Just to be sure nothing unexpected happens, I tested that this doesn't
cause any changes in behavior by outputting bidi-transformed versions
of all strings in strings.xml to a file for both our Arabic and Persian
localizations before and after the update, and confirming that the
files are the same.

desktop_version/src/FontBidi.cpp

@@ -1,6 +1,7 @@
 #include "FontBidi.h"
 
 #include <SDL.h>
+#include <SheenBidi/SheenBidi.h>
 
 #include "Alloc.h"
 #include "UTF8.h"
@@ -8,7 +9,6 @@
 extern "C"
 {
 #include <c-hashmap/map.h>
-#include <SheenBidi.h>
 }
 
 namespace font