fix(menu): export menu interfaces (#27227)

Issue number: N/A

---------

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## What is the current behavior?
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When updating to Stencil v3
([commit](https://github.com/ionic-team/ionic-framework/commit/1a8bd6d8c6a5227f803250722442199cbfa3510d#diff-83006355bd18aced9f88fd3b27ff6a40527c713b314145c2a34ad54b6361fa87)),
we removed many manual exports that are automatically exported by
Stencil. This change included removing the `MenuI` type from being
exported. This type is not automatically exported since it is not
directly associated to a `@Prop`.

This causes implementers that previously had a typed value against
`MenuI` in v6 for registering menus, to have to import from:
```ts
import { MenuI } from "@ionic/core/dist/types/components/menu/menu-interface";
```

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

- Re-exports the `MenuI` interface


## 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. -->