refactor: reduce redundancy

Author: Seli0303

src/fragments/forms/map-form/components/optimization/components/edit-dialog/edit-dialog.js

@@ -107,11 +107,11 @@ export default {
       }
     },
     headerText () {
-      if (this.editId === 0) {
-        return this.content.header
-      } else {
-        return this.content.header + ' - editing ' + this.editId
+      let editing = ''
+      if (!(this.editId === 0)) {
+        editing = ' - editing ' + this.editId
       }
+      return this.content.header + editing
     },
     // returns true if start and end point are the same
     sameStartEndPoint () {