Backport PR matplotlib#26545: Fix size inferral when using cairocffi

Author: ksunden

lib/matplotlib/backends/backend_cairo.py

@@ -95,7 +95,7 @@ def set_context(self, ctx):
             rect, *rest = ctx.copy_clip_rectangle_list()
             if rest:
                 raise TypeError("Cannot infer surface size")
-            size = rect.width, rect.height
+            _, _, *size = rect
             ctx.restore()
         self.gc.ctx = ctx
         self.width, self.height = size