fix: 解决初始化脑图时如果为readyonly history不会初始化的问题

simple-mind-map/index.js

@@ -489,6 +489,9 @@ class MindMap {
       this.execCommand('CLEAR_ACTIVE_NODE')
     }
     this.opt.readonly = isReadonly
+    if (!isReadonly) {
+      this.command.originAddHistory()
+    }
     this.emit('mode_change', mode)
   }