[Bug]: When remote certificate is invalid, client refuses to cancel attempts for connection

# Bug description

When the desktop application correctly reports "Untrusted Certificate", it continues, despite requests to cancel, reproducing the same warning, through a modal warning box that blocks access to the application.

# Steps to reproduce

1. In the Nextcloud Desktop, configure a server account for a working remote server, including a certificate correctly installed on the web server.
2. Establish and complete synchronization for some folders.
3. Exit the desktop application.
4. Install an invalid certificate on the web server, such as one corresponding to a different domain.
5. Open the desktop application.
6. When the applications complains about the certificate (see below image), choose *Cancel*, to avoid continuing attempts to establish a secure connection.
7. *Wait for a few minutes, until the warning returns.*

*The warning repeatedly returns despite attempts to cancel the operation.*

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# Expected behavior

Once the button is selected for *Cancel*, the operation should abort, at least until the next time the application launches, or until the user manually invokes an attempt to synchronize with the particular remote server. In the meantime, the client should update its internal state to reflect that the user chose to cancel further attempts to connect.

# System environment

- Operating system: Linux (Linux Mint 21.2)
- Package: Distro package manager
- Nextcloud Desktop Client version: 3.4.2