Merge pull request dolphin-emu#8643 from jordan-woyak/mapping-race-fix

InputCommon/DolphinQt: Mapping related race fixes and cleanups.

Author: spycrab

Source/Core/DolphinQt/Config/Mapping/IOWindow.cpp

@@ -544,7 +544,7 @@ void InputStateDelegate::paint(QPainter* painter, const QStyleOptionViewItem& op
   rect.setWidth(rect.width() * std::clamp(state, 0.0, 1.0));
 
   // Create a temporary indicator object to retreive color constants.
-  MappingIndicator indicator(nullptr);
+  MappingIndicator indicator;
 
   painter->save();