Moved __future__ import to beginning of file

[radarhere]

Helps #2625.

oss-fuzz coverage has started failing after #7631 - https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=65341&sort=-opened&can=1&q=proj%3Apillow

Syntax error in /src/Pillow/Tests/oss-fuzz/fuzz_font.py
File "/src/Pillow/Tests/oss-fuzz/fuzz_font.py", line 27
from __future__ import annotations
^
SyntaxError: from __future__ imports must occur at the beginning of the file

[hugovk]

I'm surprised the linters didn't catch it. Do you know what oss-fuzz is "Analyzing" when it fails and if other files will trigger it? Or we can merge and see the next build.

[radarhere]

While the initial report was about Tests/oss-fuzz/fuzz_font.py, my attempt to replicate gave an error about Tests/oss-fuzz/fuzz_pillow.py, so I've updated that as well.

My attempts to convince my oss-fuzz fork to look at this PR's branch aren't working however, so no, I can't guarantee that there aren't other fixes that need to be made.

[radarhere]

#7649 was the solution to this in the end.