remove QgsMapCanvas.useImageToRender in db_manager (fixes #9942)

Author: jef-n

python/plugins/db_manager/layer_preview.py

@@ -39,7 +39,6 @@ def __init__(self, parent=None):
     # reuse settings from QGIS
     settings = QSettings()
     self.enableAntiAliasing( settings.value( "/qgis/enable_anti_aliasing", False, type=bool ) )
-    self.useImageToRender( settings.value( "/qgis/use_qimage_to_render", False, type=bool ) )
     action = settings.value( "/qgis/wheel_action", 0, type=float )
     zoomFactor = settings.value( "/qgis/zoom_factor", 2, type=float )
     self.setWheelAction( QgsMapCanvas.WheelAction(action), zoomFactor )