Gap between macOS menubar and popup window

### ⚠️ 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

There is a vertical gap between the macOS menubar and the Nextcloud popup window. All other native macOS menubar entries do not have that gap, but their windows directly touch the menubar.

### Steps to reproduce

1. Click on the Nextcloud menubar entry
2. Observe the vertical gap between the menubar and the window (indicated by the blue arrow):

### Expected behavior

Native menubar entries do not produce that gap:

### Which files are affected by this bug

N/A

### Operating system

macOS

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

macOS 26.6.2

### Installation method

Official Installer for macOS 13 and later

### Nextcloud Server version

34.0.4

### Nextcloud Desktop Client version

34.0.3

### 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?

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

### Nextcloud Server logs

```shell

```

### Additional info

_No response_