fix text update

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

         public override int GetHashCode() {
             return (style != null ? style.GetHashCode() : 0);
         }
+        
+        public static bool operator ==(InlineSpan left, InlineSpan right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(InlineSpan left, InlineSpan right) {
+            return !Equals(left, right);
+        }
     }
 }

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

             get { return _text; }
             set {
                 D.assert(value == null || value.debugAssertIsValid());
-                if ((_text == null && value == null) || (_text != null && text.Equals(value))) {
+                if (_text == value) {
                     return;
                 }