docs: center app logo in animated hero

Author: Yannam-Builds

.github/assets/ironlog-hero.svg

@@ -1,7 +1,5 @@
 <div align="center">
 
-<img src="app/src/main/res/drawable-xxxhdpi/splashscreen_logo.png" width="112" alt="IronLog app logo">
-
 ![IronLog — Train. Recover. Prove it.](.github/assets/ironlog-hero.svg)
 
 [![Android CI](https://github.com/Yannam-Builds/Ironlog/actions/workflows/android.yml/badge.svg)](https://github.com/Yannam-Builds/Ironlog/actions/workflows/android.yml)