Change how landscape pages are rotated, for printing, with enablePrintAutoRotate = true set

Currently landscape pages are rotated *clockwise*, which for most documents feel wrong since holding the printed pages at their *left* edge causes the landscape pages to be viewed "upside down".
In general, since most documents are LTR ones, it feels more appropriate to instead rotate landscape pages *counterclockwise* for printing.

web/base_viewer.js

@@ -1365,7 +1365,7 @@ class BaseViewer {
       return {
         width: size.height,
         height: size.width,
-        rotation: (size.rotation + 90) % 360,
+        rotation: (size.rotation - 90) % 360,
       };
     });
   }