BUG: Avoid scaling cropbox twice (#1314)

When a PDF document has no crobox, artbox, etc, they are fallback to mediabox.
As they are lazy, self.cropbox returns the mediabox copy which already was scaled.

Changing the order avoids this issue

Author: yegorLitvinov

PyPDF2/_page.py

@@ -952,11 +952,11 @@ def scale(self, sx: float, sy: float) -> None:
         :param float sy: The scaling factor on vertical axis.
         """
         self.add_transformation((sx, 0, 0, sy, 0, 0))
-        self.mediabox = self.mediabox.scale(sx, sy)
         self.cropbox = self.cropbox.scale(sx, sy)
         self.artbox = self.artbox.scale(sx, sy)
         self.bleedbox = self.bleedbox.scale(sx, sy)
         self.trimbox = self.trimbox.scale(sx, sy)
+        self.mediabox = self.mediabox.scale(sx, sy)
         if PG.VP in self:
             viewport = self[PG.VP]
             if isinstance(viewport, ArrayObject):