getScrollingParent() causes runtime error in custom elements

[corrupt]

Overview of the problem

Oruga version: [0.8.2]
Vuejs version: [3.1.1]
OS/Browser: macOS 14.2.1/Firefox 121 (64-bit)
OS/Browser: macOS 14.2.1/Chrome 120 (64-bit)

Description

The getScrollingParent() function will blindly traverse up the DOM tree, looking for a parent element that would scroll the current one.
When Oruga is used in custom elements, that traversal will eventually lead .parentElement to resolve to null upon reaching the root of the shadow DOM, which is not accounted for.

Steps to reproduce

I've created a minimal example to reproduce this.

To try it out:

git clone https://github.com/corrupt/oruga-taginput-test.git
cd oruga-taginput-test
npm install
npx vite build && npx vite preview

Then visit http://127.0.0.1:4173/, open dev console, click in the control and type j.

Expected behavior

No error should occur

Actual behavior

TypeError: Window.getComputedStyle: Argument 1 is not an object. is thrown.