examples: Fix density handling in acoustic

[mloubout]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 66.66667% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 92.10%. Comparing base (0d6197b) to head (510aa12).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
examples/seismic/tti/operators.py	66.66%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2716      +/-   ##
==========================================
- Coverage   92.11%   92.10%   -0.01%     
==========================================
  Files         248      248              
  Lines       49644    49654      +10     
  Branches     4367     4368       +1     
==========================================
+ Hits        45729    45734       +5     
- Misses       3208     3213       +5     
  Partials      707      707              

Flag	Coverage Δ
pytest-gpu-aomp-amdgpuX	71.07% <66.66%> (-0.01%)	⬇️
pytest-gpu-nvc-nvidiaX	72.04% <66.66%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[FabioLuporini]

Uncontroversial