fix Image & text errors

com.unity.uiwidgets/Runtime/cupertino/text_theme.cs

             TextStyle pickerTextStyle = null,
             TextStyle dateTimePickerTextStyle = null
         ) {
-            D.assert((_navActionTextStyle != null && _actionTextStyle != null) || _primaryColor != null);
+            D.assert((_navActionTextStyle != null && _actionTextStyle != null) || _primaryColor != null);
             _textStyle = textStyle;
             _actionTextStyle = actionTextStyle;
             _tabLabelTextStyle = tabLabelTextStyle;

com.unity.uiwidgets/Runtime/painting/alignment.cs

         }
 
         public override Alignment resolve(TextDirection? direction) {
-            D.assert(direction != null);
+            direction = direction ?? TextDirection.ltr;
             switch (direction) {
                 case TextDirection.rtl:
                     return new Alignment(_x - _start, _y);

com.unity.uiwidgets/Runtime/rendering/image.cs

             properties.add(new DiagnosticsProperty<bool>("invertColors", invertColors));
             properties.add(new EnumProperty<FilterQuality>("filterMode", filterQuality));
             properties.add(new FlagProperty("matchTextDirection", value: matchTextDirection, ifTrue: "match text direction"));
-            properties.add(new EnumProperty<TextDirection>("textDirection", (TextDirection)textDirection, defaultValue: null));
+            properties.add(new EnumProperty<TextDirection?>("textDirection", textDirection, defaultValue: null));
 
         }
     }

com.unity.uiwidgets/Runtime/rendering/shifted_box.cs

         TextDirection? _textDirection;
         
         protected void alignChild() {
+            _resolve();
             D.assert(child != null);
             D.assert(!child.debugNeedsLayout);
             D.assert(child.hasSize);