[Bug]: Two instances of Nextcloud Desktop running in parallel

### ⚠️ 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've searched 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

Lately, I see regularly that there are two instances of Nextcloud Desktop running after first logging in. I see two Nextcloud Desktop icons:
And ps shows this:

### Steps to reproduce

1. Start the computer
2. Wait for the system to be booted
3. Log in
Note that two instances of Nextcloud Desktop are started

### Expected behavior

Only one instance of Nextcloud Desktop running at the same time

### Which files are affected by this bug

n.a.

### Operating system

Linux

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

Fedora 35

### Package

Distro package manager

### Nextcloud Server version

22.2.6

### Nextcloud Desktop Client version

3.5.1

### Is this bug present after an update or on a fresh install?

Updated from a minor version (ex. 3.4.2 to 3.4.4)

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

Encryption is Disabled

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

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

### Nextcloud Server logs

_No response_

### Additional info

For (still unknown to me) reasons, my system is slow on disk access, and starting applications takes a relative long time.