fix: TProfile reading and writing logic

[ariostas]

This PR aims to fix the IO logic for TProfiles. These issues were brought up in #1531 and #1533.

The fixes here were made primarily made with Claude, with some manual tweaking afterwards. I did extensive questioning and I went through the changes carefully, and I ended up convincing myself that they're right. But I'd appreciate if someone else who is more familiar with TProfiles can also take a look.

@wiso, would you be able to have a look? I'll add the example you posted in #1532 as a test.

[codecov]

Codecov Report

❌ Patch coverage is 86.95652% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.66%. Comparing base (3c45812) to head (db301e0).
⚠️ Report is 2 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/uproot/writing/identify.py	85.71%	4 Missing and 1 partial ⚠️
src/uproot/behaviors/TProfile.py	88.23%	2 Missing and 2 partials ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
src/uproot/behaviors/TProfile.py	85.87% <88.23%> (+4.39%)	⬆️
src/uproot/writing/identify.py	73.36% <85.71%> (+1.61%)	⬆️