Layout flashing when use custom command

**Describe the bug**
as title

**To Reproduce**
config:
```yaml
# Config relating to the Lazygit UI
gui:
# Number from 0 to 1.0.
sidePanelWidth: 0.33
# If true, increase the height of the focused side window; creating an accordion effect.
expandFocusedSidePanel: false
showBottomLine: false
customCommands:
- key:
command: 'echo "hello"'
context: "files"
```
press ``, layout changes as if expandFocusedSidePanel and showBottomLine are both true for a very brief moment.

**Expected behavior**
no flashing

https://github.com/user-attachments/assets/6d204977-7780-416c-87d6-f6ce8dff8558

**Screenshots**
If applicable, add screenshots to help explain your problem.
wrong moment：

**Version info:**
Latest main

**Additional context**
Add any other context about the problem here.

**Note:** please try updating to the latest version or [manually building](https://github.com/jesseduffield/lazygit/#manual) the latest `master` to see if the issue still occurs.