fix(neon_framework): Fix Android push notification icon

[provokateurin]

Before/after:

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 28.79%. Comparing base (a01e746) to head (296563d).
Report is 10 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2576   +/-   ##
=======================================
  Coverage   28.79%   28.79%           
=======================================
  Files         370      370           
  Lines      136490   136490           
=======================================
  Hits        39296    39296           
  Misses      97194    97194           

Flag	Coverage Δ		*Carryforward flag
account_repository	98.47% <ø> (ø)
cookie_store	99.48% <ø> (ø)		Carriedforward from a01e746
dashboard_app	96.05% <ø> (ø)
dynamite	31.05% <ø> (ø)		Carriedforward from a01e746
dynamite_end_to_end_test	61.69% <ø> (ø)		Carriedforward from a01e746
dynamite_runtime	85.40% <ø> (ø)		Carriedforward from a01e746
interceptor_http_client	97.18% <ø> (ø)		Carriedforward from a01e746
neon_dashboard	96.05% <ø> (ø)		Carriedforward from a01e746
neon_framework	61.00% <ø> (ø)
neon_http_client	97.50% <ø> (ø)		Carriedforward from a01e746
neon_notifications	100.00% <ø> (ø)		Carriedforward from a01e746
neon_storage	94.66% <ø> (ø)		Carriedforward from a01e746
neon_talk	99.45% <ø> (ø)		Carriedforward from a01e746
nextcloud	24.26% <ø> (ø)		Carriedforward from a01e746
notifications_app	97.40% <ø> (ø)
notifications_push_repository	98.11% <ø> (ø)
sort_box	90.90% <ø> (ø)		Carriedforward from a01e746
talk_app	98.94% <ø> (ø)

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

Files with missing lines	Coverage Δ
...kages/neon_framework/lib/src/utils/push_utils.dart	97.02% <ø> (ø)