Evaluation UI does not render if there is more than one folder in the project

If you have a project with two or more folders, ADK web starts in an empty state and you need to choose which agent to work on using the agent selector. If you click on an agent and then go to the eval tab, the eval tab will be empty. If you refresh the page and re-select the eval tab, the UI render normally.

It doesn't matter if the extra folders are agents or just project folders.

**To Reproduce**

```shell
mkdir adk-ui-test && cd adk-ui-test
uv init
uv add google-adk google-adk[eval]
uv run adk create hello
uv run adk create goodbye
uv run adk web
```

Access the web UI, select an agent and click on the Eval tab. It will be empty. Hit refresh and click on the Eval tab again - the missing UI components will appear.

**Expected behavior**
The Eval UI components should appear always if the selected folder is an agent.

**Screenshots**

Before refresh:

After refresh:

**Desktop (please complete the following information):**
- OS: macOS
- Python version(python -V): 3.12
- ADK version(pip show google-adk): 1.18

**Model Information:**
- Are you using LiteLLM: No
- Which model is being used(e.g. gemini-2.5-pro): gemini-2.5-flash

**Additional context**
N/A