using encoderinfo for saving also for the non-primary images

[bigcat88]

Fixes #308

I have no idea now why I originally wrote that this data was only transferred for the main image.

The change is small, in theory it shouldn't break anything, and in the future it will probably be necessary after a big refactoring (with Pillow 12?) to use encoderinfo for all these parameters, so the change is useful.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.89%. Comparing base (4c24a2e) to head (c9b6a7c).
Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #313      +/-   ##
==========================================
- Coverage   99.89%   99.89%   -0.01%     
==========================================
  Files          10       10              
  Lines         976      975       -1     
==========================================
- Hits          975      974       -1     
  Misses          1        1              

Files with missing lines	Coverage Δ
pillow_heif/as_plugin.py	100.00% <100.00%> (ø)