[List]: list item in the panel has no border when nested

Bug Description

List does not provide the expand/collapse functionality natively.
However, in some cases where the items are private, it's necessary to hide them by default by collapsing the group. To achieve so, we plan to put the group of items into a panel. But the items have no bottom border as the separator when doing so.

reproduction steps:

1. open the first playground link in the List document.

2. import "@ui5/webcomponents/dist/Panel.js";

3. modify the html to `
   

    <ui5-li icon="nutrition-activity" description="Tropical plant with an edible fruit" additional-text="In-stock"
        additional-text-state="Positive">Pineapple</ui5-li>
    <ui5-li icon="nutrition-activity" description="Occurs between red and yellow" additional-text="Expires"
        additional-text-state="Critical">Orange</ui5-li>
    <ui5-li icon="nutrition-activity" description="The yellow lengthy fruit" additional-text="Re-stock"
        additional-text-state="Information">Blueberry</ui5-li>
    <ui5-li icon="nutrition-activity" description="The tropical stone fruit" additional-text="Re-stock"
        additional-text-state="Negative">Mango</ui5-li>
     <ui5-panel>
   

   `

4. watch the preview that the bottom border of the list item is not shown

Affected Component

List and Panel

Expected Behaviour

the list item should have the option to show its bottom border.

Isolated Example

https://sap.github.io/ui5-webcomponents/play/#eyJpbmRleC5odG1sIjp7Im5hbWUiOiJpbmRleC5odG1sIiwiY29udGVudCI6IjwhLS0gcGxheWdyb3VuZC1mb2xkIC0tPlxuPCFET0NUWVBFIGh0bWw-XG48aHRtbCBsYW5nPVwiZW5cIj5cblxuXG48aGVhZD5cbiAgICBcbiAgICA8c3R5bGU-XG4gICAgICAqOm5vdCg6ZGVmaW5lZCkge1xuICAgICAgICBkaXNwbGF5OiBub25lO1xuICAgICAgfVxuXG4gICAgaHRtbCB7XG4gICAgICBmb3JjZWQtY29sb3ItYWRqdXN0OiBub25lO1xuICAgIH1cbiAgICA8L3N0eWxlPlxuXG4gICAgPG1ldGEgY2hhcnNldD1cIlVURi04XCI-XG4gICAgPG1ldGEgbmFtZT1cInZpZXdwb3J0XCIgY29udGVudD1cIndpZHRoPWRldmljZS13aWR0aCwgaW5pdGlhbC1zY2FsZT0xLjBcIj5cbiAgICA8dGl0bGU-U2FtcGxlPC90aXRsZT5cbjwvaGVhZD5cblxuPGJvZHkgc3R5bGU9XCJiYWNrZ3JvdW5kLWNvbG9yOiB2YXIoLS1zYXBCYWNrZ3JvdW5kQ29sb3IpXCI-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-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

Steps to Reproduce

No response

Log Output, Stack Trace or Screenshots

No response

Priority

None

UI5 Web Components Version

2.3.0

Browser

Chrome, Edge, Firefox, Safari

Operating System

No response

Additional Context

No response

Organization

SFSF

Declaration

• I’m not disclosing any internal or sensitive information.