Sleek blanks out when task contains markdown link with empty label

[amariusz]

Bug Report

App Version: Enter the version number, e.g., 1.2.3 2.0.13 (local build)

Platform: Linux

Installation Method: deb

Expected Behavior: Display as regular text.

Actual Behavior: All UI disappears, blank window remain.

Steps to Reproduce:

1. Add task with []() or [](https://google.com)
2. Click Update
3. Observe the unexpected behavior.

Screenshots: If applicable, include screenshots that demonstrate the bug.