collapsible does not work if summary is not on new line

[come-nc]

Describe the bug

This is not supported:

<details><summary>title</summary>

content

</details>

But this is:

<details>
<summary>title</summary>

content

</details>

This is especially visible because we use the former for our support reports.

Server details:

• Nextcloud version: master
• PHP Version: [e.g. 8.2]
• Database: [e.g. MariaDB 10.6]

Client details:

• OS: [e.g. Windows/macOS/Ubuntu]
• Browser: [e.g. Firefox, Chrome]
• Browser version: [e.g. 22]
• Device: [e.g. iPhone6, desktop]