Shortened path in tab label works only for the first tab

As said in the title...

<img width="1826" height="39" alt="Image" src="https://github.com/user-attachments/assets/6daece33-3aa4-4316-9814-ff4f2172f323" />

```
$ guake --version
Guake Terminal: 3.11.dev0
VTE: 0.82.3
VTE runtime: 0.82.3
Gtk: 3.24.51
```
