Support fixed seed in vue (#7510)

A small change pulled out of #7095 to make disabling the current control
option swap to 'fixed' instead of doing nothing.

Resolves #7468

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7510-Support-fixed-seed-in-vue-2ca6d73d365081b0a723ebc97b921305)
by [Unito](https://www.unito.io)

src/renderer/extensions/vueNodes/widgets/components/NumberControlPopover.vue

@@ -150,7 +150,12 @@ const handleEditSettings = () => {
           <ToggleSwitch
             :model-value="isActive(option.mode)"
             class="flex-shrink-0"
-            @update:model-value="handleToggle(option.mode)"
+            @update:model-value="
+              (v) =>
+                v
+                  ? handleToggle(option.mode)
+                  : handleToggle(NumberControlMode.FIXED)
+            "
           />
         </div>
       </div>