pbio/image/fonts: fix getdata being deprecated in Pillow 12.1.0.

Author: schodet

lib/pbio/src/image/fontconvert.py

@@ -154,7 +154,7 @@ def load_image(self, filename: str) -> None:
         cols = (self.last - self.first + 1 + (rows - 1)) // rows
         gwidth = imwidth // cols
         gheight = self.size
-        data = list(im.getdata())
+        data = im.get_flattened_data()
 
         self.line_height = gheight
         self.top_max = gheight