fix(ios/fabric): stop overriding JS width in Yoga layout

The `adopt` method in `ComponentDescriptors.h` called `setSize()` with
both width and height from `sizeThatFits:UILayoutFittingCompressedSize`.
Because `UIDatePicker` has a native minimum width of 280pt, this forced
a fixed width on the Yoga node, overriding any JS style such as
`width: "100%"`.

Only set the **height** from the native measurement and let the JS side
control the width through regular Yoga styles.

Adds `setMeasuredHeight()` to `RNDateTimePickerShadowNode` which sets
only `yoga::Dimension::Height` on the Yoga node style, leaving the
width dimension untouched.

Fixes #1014

Author: Scr3nt

ios/fabric/cpp/react/renderer/components/RNDateTimePicker/ComponentDescriptors.h

@@ -20,13 +20,12 @@ class RNDateTimePickerComponentDescriptor final : public ConcreteComponentDescri
 
     void adopt(ShadowNode& shadowNode) const override {
       auto& pickerShadowNode = static_cast<RNDateTimePickerShadowNode&>(shadowNode);
-      auto& layoutableShadowNode = static_cast<YogaLayoutableShadowNode&>(pickerShadowNode);
 
       auto state = std::static_pointer_cast<const RNDateTimePickerShadowNode::ConcreteState>(shadowNode.getState());
       auto stateData = state->getData();
 
-      if(stateData.frameSize.width != 0 && stateData.frameSize.height != 0) {
-        layoutableShadowNode.setSize(Size{stateData.frameSize.width, stateData.frameSize.height});
+      if(stateData.frameSize.height != 0) {
+        pickerShadowNode.setMeasuredHeight(stateData.frameSize.height);
       }
 
       ConcreteComponentDescriptor::adopt(shadowNode);

ios/fabric/cpp/react/renderer/components/RNDateTimePicker/ShadowNodes.h

@@ -33,6 +33,13 @@ class JSI_EXPORT RNDateTimePickerShadowNode final : public ConcreteViewShadowNod
         traits.set(ShadowNodeTraits::Trait::LeafYogaNode);
         return traits;
     }
+
+    void setMeasuredHeight(float height) const {
+        auto style = yogaNode_.style();
+        style.setDimension(yoga::Dimension::Height, yoga::StyleSizeLength::points(height));
+        yogaNode_.setStyle(style);
+        yogaNode_.setDirty(true);
+    }
 };
 
 } // namespace react