chore(chart): make chart point marker style optional

Author: singerla

src/modify/modify-chart.ts

@@ -280,13 +280,21 @@ export class ModifyChart {
           'c:spPr': {
             modify: ModifyColorHelper.solidFill(style.color),
           },
-          'c:marker': {
-            isRequired: false,
-            children: {
-              'c:spPr': {
-                modify: ModifyColorHelper.solidFill(style.marker?.color),
-              }
-            }
+          ...this.chartPointMarker(style.marker)
+        }
+      }
+    }
+  }
+
+  chartPointMarker = (markerStyle: ChartValueStyle['marker']): ModificationTags => {
+    if(!markerStyle) return
+
+    return {
+      'c:marker': {
+        isRequired: false,
+        children: {
+          'c:spPr': {
+            modify: ModifyColorHelper.solidFill(markerStyle.color),
           }
         }
       }