chore(vue): add missing routerAnimation type (#28094)

Issue number: N/A

---------

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## What is the current behavior?
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The Vue Router implementation [assigns data to the `routerAnimation` on
the view
item](cddefd1548/packages/vue/src/components/IonRouterOutlet.ts (L165-L170)),
but the [type does not exist on the `ViewItem`
interface](https://github.com/ionic-team/ionic-framework/blob/main/packages/vue-router/src/types.ts#L62-L76).
The actual routing implementation does not make use of the type, but
this is backfilling the information when we wire up the types to the
implementation.

## What is the new behavior?
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this PR. -->

- Adds the missing type for `routerAnimation` to the `ViewItem`

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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and migration path for existing applications below. -->


## Other information

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screenshots of how the component looks before and after the change. -->

packages/vue-router/src/types.ts

@@ -73,6 +73,7 @@ export interface ViewItem {
   vueComponentRef: Ref;
   params?: { [k: string]: any };
   vueComponentData: VueComponentData;
+  routerAnimation?: AnimationBuilder;
 }
 
 export interface ViewStacks {