Update ci.yaml

Author: JLBegin

.github/workflows/ci.yaml

@@ -52,14 +52,11 @@ jobs:
           python -c "from pytissueoptics.rayscattering.opencl import OPENCL_OK; assert OPENCL_OK"
 
       - name: Test headless PyQt5
-#        env:
-#          QT_QPA_PLATFORM: offscreen
         run: |
           python -c "from PyQt5.QtWidgets import QApplication, QLabel; app = QApplication([]); QLabel('Test');"
 
       - name: Run tests
         env:
-          QT_QPA_PLATFORM: offscreen
           PTO_DEVICE_INDEX: 0
           PTO_N_WORK_UNITS: 128
           PTO_MAX_MEMORY_MB: 1024