fix: set row margin boundary error

src/editor/core/draw/Draw.ts

@@ -1188,7 +1188,7 @@ export class Draw {
     const { defaultBasicRowMarginHeight, defaultRowMargin, scale } =
       this.options
     return (
-      defaultBasicRowMarginHeight * (el.rowMargin || defaultRowMargin) * scale
+      defaultBasicRowMarginHeight * (el.rowMargin ?? defaultRowMargin) * scale
     )
   }
 
@@ -1227,7 +1227,7 @@ export class Draw {
       const curRow: IRow = rowList[rowList.length - 1]
       const element = elementList[i]
       const rowMargin =
-        defaultBasicRowMarginHeight * (element.rowMargin || defaultRowMargin)
+        defaultBasicRowMarginHeight * (element.rowMargin ?? defaultRowMargin)
       const metrics: IElementMetrics = {
         width: 0,
         height: 0,

src/editor/core/range/RangeManager.ts

@@ -430,7 +430,7 @@ export class RangeManager {
     const color = curElement.color || null
     const highlight = curElement.highlight || null
     const rowFlex = curElement.rowFlex || null
-    const rowMargin = curElement.rowMargin || this.options.defaultRowMargin
+    const rowMargin = curElement.rowMargin ?? this.options.defaultRowMargin
     const dashArray = curElement.dashArray || []
     const level = curElement.level || null
     const listType = curElement.listType || null