Fixes a re-render error within widget extensions

This was caused by the original object getting overwritten by
Vues reactivity.

app/assets/javascripts/vue_merge_request_widget/components/extensions/container.js

@@ -10,20 +10,23 @@ export default {
   render(h) {
     if (extensions.length === 0) return null;
 
-    return h(
-      'div',
-      {},
-      extensions.map((extension) =>
-        h(extension, {
-          props: extension.props.reduce(
-            (acc, key) => ({
-              ...acc,
-              [key]: this.mr[key],
-            }),
-            {},
-          ),
-        }),
+    return h('div', {}, [
+      ...extensions.map((extension) =>
+        h(
+          { ...extension },
+          {
+            props: {
+              ...extension.props.reduce(
+                (acc, key) => ({
+                  ...acc,
+                  [key]: this.mr[key],
+                }),
+                {},
+              ),
+            },
+          },
+        ),
       ),
-    );
+    ]);
   },
 };