fix 0018975: 【图像测量】【小动物】辛普森测量后生成测量结果，此时切换其他测量项，测量结果会自动消失，应能保留测量结果

lib/process/calcuators/three_distance.dart

@@ -91,6 +91,8 @@ class PercentMAMCalculator extends Calculator<LWHStraightLine, double> {
     final h = findChildFeature(ref.h);
     if (l == null && w == null && h == null) return;
 
+    updateStringValue("");
+
     double? mapse;
     double? lvidd;
     double? lvids;

lib/process/primitives/combos/lv_study.dart

@@ -13,7 +13,6 @@ class LvStudy extends TopMeasureItem<StraightLineGroupFeature> {
   LvStudy(ItemMeta meta, {this.ifVertical = false, this.ifTimeSpan = false})
       : super(meta) {
     for (final childMeta in meta.childItems) {
-      print(childMeta);
       IMeasureItem childItem;
       if (childMeta.measureType == "VerticalDistance") {
         // measureType

lib/process/primitives/simpson_path.dart

@@ -80,6 +80,7 @@ class SimpsonPath extends AreaItemAbstract with AutoSnapMixin {
             lvSimpsonStep = LvSimpsonStep.done;
             state = ItemStates.finished;
             // CaliperExtension.ShowCaliper();
+            doFeatureFinish();
           } else {
             final lineLen = (args - firstPoint!).length;
             if ((feature!.innerPoints.length > 3 &&