[backport core/1.42] fix: make gradient_stops enumerable so it survives object spread (#10866)

Backport of #10406 to `core/1.42`

Automatically created by backport workflow.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10866-backport-core-1-42-fix-make-gradient_stops-enumerable-so-it-survives-object-spread-33a6d73d3650819086dfc5cd7a395aed)
by [Unito](https://www.unito.io)

Co-authored-by: Terry Jia <terryjia88@gmail.com>

src/extensions/core/customWidgets.test.ts

@@ -30,6 +30,7 @@ describe('PrimitiveFloat widget type bridging', () => {
     })
 
     Object.defineProperty(widget.options, 'gradient_stops', {
+      enumerable: true,
       get: () => properties.gradient_stops,
       set: (v) => {
         properties.gradient_stops = v

src/extensions/core/customWidgets.ts

@@ -169,6 +169,7 @@ function onCustomFloatCreated(this: LGraphNode) {
   })
 
   Object.defineProperty(valueWidget.options, 'gradient_stops', {
+    enumerable: true,
     get: () => this.properties.gradient_stops,
     set: (v) => {
       this.properties.gradient_stops = v