[Bug]: evaluating_adk_agent uses predicted_trajectory instead of reference_trajectory

### File Name

https://github.com/GoogleCloudPlatform/generative-ai/blob/main/gemini/evaluation/evaluating_adk_agent.ipynb

### What happened?

In the Prepare Agent Evaluation dataset of the [evaluating_adk_agent](https://github.com/GoogleCloudPlatform/generative-ai/blob/main/gemini/evaluation/evaluating_adk_agent.ipynb) notebook, there is a critical typo:
predicted_trajectory should be reference_trajectory

```
eval_data = {
"prompt": [
"Get price for smartphone",
"Get product details and price for headphones",
"Get details for usb charger",
"Get product details and price for shoes",
"Get product details for speaker?",
],
"predicted_trajectory": [. # should be reference_trajectory
[
{
"tool_name": "get_product_price",
"tool_input": {"product_name": "smartphone"},
}
...
```
compare it with the correct eval_data in this notebook [evaluating_langgraph_agent](https://github.com/GoogleCloudPlatform/generative-ai/blob/main/gemini/evaluation/evaltask_approach/evaluating_langgraph_agent.ipynb):

```

eval_data = {
"prompt": [
"Get price for smartphone",
"Get product details and price for headphones",
"Get details for usb charger",
"Get product details and price for shoes",
"Get product details for speaker?",
],
"reference_trajectory": [
[
{
"tool_name": "get_product_price",
"tool_input": {"product_name": "smartphone"},
}
],

```
### Relevant log output

```shell

```

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