Notification timeout removed for critical errors

[VandalByte]

Description

This PR removes the timeout for error notifications in the Vorta. Instead of disappearing after 5 seconds, error notifications will remain until the user dismisses them manually.

time = 0 if level == 'error' else 5000

This ensures that the user has a better chance to review critical error messages and take necessary actions, even if they don't see the notification immediately.

Related Issue

Resolves #2045

How Has This Been Tested?

Tested on Linux Mint 22.1
Testing was done by calling the notification class DBusNotifications

if __name__ == "__main__":
    from unittest.mock import MagicMock
    SettingsModel.get = MagicMock(return_value=MagicMock(value=True))

    notifier = DBusNotifications()
    notifier.deliver('Test Notify', 'This is a test notification', level='error')
    print("Test Notification ran...")

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have read the CONTRIBUTING guide.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

I provide my contribution under the terms of the license of this repository and I affirm the Developer Certificate of Origin.