fix(neon_framework): Use inverted logo in example flatpak .desktop icon

[provokateurin]

The background style doesn't work, so using the normal logo results in a white icon with transparent background which looks ugly and boring. Now it is at least blue 🎉

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.84%. Comparing base (7b898c9) to head (0298996).
Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2595   +/-   ##
=======================================
  Coverage   28.84%   28.84%           
=======================================
  Files         370      370           
  Lines      136488   136488           
=======================================
  Hits        39369    39369           
  Misses      97119    97119           

Flag	Coverage Δ		*Carryforward flag
account_repository	98.47% <ø> (ø)
cookie_store	99.48% <ø> (ø)		Carriedforward from 7b898c9
dashboard_app	96.05% <ø> (ø)
dynamite	31.05% <ø> (ø)		Carriedforward from 7b898c9
dynamite_end_to_end_test	61.69% <ø> (ø)		Carriedforward from 7b898c9
dynamite_runtime	85.40% <ø> (ø)		Carriedforward from 7b898c9
interceptor_http_client	97.18% <ø> (ø)		Carriedforward from 7b898c9
neon_dashboard	96.05% <ø> (ø)		Carriedforward from 7b898c9
neon_framework	61.11% <ø> (ø)
neon_http_client	97.50% <ø> (ø)		Carriedforward from 7b898c9
neon_notifications	100.00% <ø> (ø)		Carriedforward from 7b898c9
neon_storage	94.66% <ø> (ø)		Carriedforward from 7b898c9
neon_talk	99.45% <ø> (ø)		Carriedforward from 7b898c9
nextcloud	24.32% <ø> (ø)		Carriedforward from 7b898c9
notifications_app	97.40% <ø> (ø)
notifications_push_repository	98.11% <ø> (ø)
sort_box	90.90% <ø> (ø)		Carriedforward from 7b898c9
talk_app	98.94% <ø> (ø)

*This pull request uses carry forward flags. Click here to find out more.