[Windows] libpng warning: tRNS: invalid with alpha channel in minimal Qt application

When running a minimal Qt application (no explicit PNG resources or image loading), multiple libpng warnings appear in the console:
libpng warning: tRNS: invalid with alpha channel
**

This occurs even after upgrading to Qt 6.7.3 and cleaning the build environment. The application exits normally (code 0), but the warnings suggest an internal Qt resource conflict.

Steps to reproduce:
1. Create a new Qt Widgets project with a blank QWidget.
2. Build and run the project (MinGW 64-bit kit).
3. Observe the console output for libpng warnings.

Expected result:
No libpng warnings should appear for a minimal project.

Actual result:
Multiple "tRNS: invalid with alpha channel" warnings are logged.

Additional notes:

• The project does NOT use any PNG resources (.qrc or code-based loading).
• The warnings persist across clean rebuilds and different Qt versions (tested on 6.7.3).
• Likely caused by internal Qt resources (e.g., style icons or themes).