Fixed liveness bug for null array units (#3642)

* Fixed null array units liveness

Fixed the issue where null array units sometimes still have the default stroke color, despite being dead

* Fixed format errors

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Co-authored-by: Martin Henz <henz@comp.nus.edu.sg>

Author: Oofky

src/features/cseMachine/components/ArrayNullUnit.tsx

@@ -21,12 +21,17 @@ export class ArrayNullUnit extends Visible {
     // needs to be recalculated here unlike arrayunit, as primitive value treat it as a text
     this._x = this.reference.x();
     this._y = this.reference.y();
+    const strokeColor =
+      this.reference.parent.isReferenced() && this.reference.parent.isEnclosingFrameLive()
+        ? defaultStrokeColor()
+        : fadedStrokeColor();
+
     return (
       <KonvaLine
         {...ShapeDefaultProps}
         key={Layout.key++}
         points={[this.x(), this.y() + this.height(), this.x() + this.width(), this.y()]}
-        stroke={this.reference.parent.isReferenced() ? defaultStrokeColor() : fadedStrokeColor()}
+        stroke={strokeColor}
         hitStrokeWidth={Config.DataHitStrokeWidth}
         ref={this.ref}
         listening={false}