Small option property cleanup (#3577)

* Notify change listeners

I can't come up with a reason for why we would not want to do this

* Remove the Display Type for OptionProperty (only used in ImGui)

* Replace extra boolean with internal anonymous addOption function

* Tiny refactor

* removed dropdown on a couple of more places

* Update optionproperty.cpp

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Co-authored-by: ElonOlsson <olssonelon@gmail.com>

modules/base/rendering/renderabledistancelabel.cpp

@@ -106,7 +106,7 @@ documentation::Documentation RenderableDistanceLabel::Documentation() {
 RenderableDistanceLabel::RenderableDistanceLabel(const ghoul::Dictionary& dictionary)
     : RenderableLabel(dictionary)
     , _nodelineId(NodeLineInfo)
-    , _distanceUnit(DistanceUnitInfo, properties::OptionProperty::DisplayType::Dropdown)
+    , _distanceUnit(DistanceUnitInfo)
     , _customUnitDescriptor(CustomUnitDescriptorInfo)
     , _precision(PrecisionInfo, 0, 0, 10)
 {