Task testing shows a connection error until the first connection check

[barmac]

Describe the bug

When I switch between diagrams, task testing shows the error initially even though the connection is OK. It seems that this is due to no connection check result being present. Perhaps we could cache the last result (RxJS switchMap way), or just have a shadow until the first result is returned.

Screen.Recording.2025-12-19.at.14.08.37.mov

Steps to reproduce

1. Open a diagram with task testing and a working connection
2. Switch between diagrams
3. now this happens

Expected behavior

Do not show error without a reason.

Environment

• OS: [e.g. MacOS 10.2, Windows 10]
• Camunda Modeler Version: [e.g. 2.0.0]
• Execution Platform: [e.g. Camunda 7, Camunda 8]
• Installed plug-ins: [...]

Additional context

No response