Invisible checkmarks for folders in Classic sync on Mac OS 27 beta

### ⚠️ Before submitting, please verify the following: ⚠️

- [x] This is a **bug**, not a question or a configuration issue.
- [x] This issue is **not** already reported on Github (I have searched for it).
- [x] Nextcloud Server and Desktop Client are **up to date**. See [Server Maintenance and Release Schedule](https://github.com/nextcloud/server/wiki/Maintenance-and-Release-Schedule) and [Desktop Releases](https://nextcloud.com/install/#install-clients) for supported versions.
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/)

### Bug description

Settings, Classic Sync, both light and dark theme in Mac OS 27 beta2 suffers from completely invisible check buttons which folders to unsync. Clicking on the right place left to folder name actually checks or unchecks it but it is a completely blind process.
...

### Steps to reproduce

1. Install sync client 33.0.7 on Mac OS with beta of Mac OS 27 on Mac mini M2 Pro
2. Set Classic sync ain Settings and try to unset some folders to not sync
3. No checkbox is visible anywhere near folder names

### Expected behavior

Folders in Classic sync in Settings must have visible check boxes.

### Which files are affected by this bug

any

### Operating system

macOS

### Which version of the operating system you are running.

27.0 Beta (26A5368g)

### Installation method

Official Installer for macOS 13 and later

### Nextcloud Server version

33.0.6

### Nextcloud Desktop Client version

33.0.7

### Did this occur after an update or on a clean installation?

Clean desktop client installation

### Are you using the Nextcloud Server Encryption module?

No

### Are you using an external user-backend?

- [x] Default internal user-backend
- [ ] LDAP or Active Directory
- [ ] SSO - SAML
- [ ] Other

### Nextcloud Server logs

```shell

```

### Additional info

_No response_

Start by reproducing the issue in Settings > Classic Sync on macOS 27 beta2, checking both light and dark themes and the folder-selection controls. Trace the Classic Sync settings UI from that entry point; done means the checkboxes beside folder names are visibly rendered and remain usable in both themes.

Written by the indexing model from the issue text.