JSException when switching activities quickly (C# input selected, Blazor Server)

### **Version**

Elsa Server: 3.6.0
Elsa Studio (Blazor Server): 3.6.0
Hosting Model: Blazor Server

---
### Issue
When using Elsa Studio (Blazor Server), rapidly switching between activities causes a JavaScript exception if an activity contains an input configured with C# expression mode.

This results in:

Console errors (Monaco editor not found / disposed object issues)
Eventually, a visible error banner in the UI

---
## Steps to Reproduce

1. Open any workflow in the designer (Blazor Server hosting)
2. Select an activity that has at least one input
3. Switch that input's expression type to **C#**
4. Quickly click between different activities on the canvas
5. Observe errors in browser console and error banner on screen

---

NOTE: The issue occurs specifically when an activity contains an input field with C# expression mode selected.

https://github.com/user-attachments/assets/e230bfc1-4611-4c8d-95db-bd9b801685b4