[Bug]: Minor bug in gemini batch prediction tutorial (trailing slash in gcs_uri breaks fsspec.glob pattern)

### File Name

`gemini/batch-prediction/intro_batch_prediction.ipynb`

### What happened?

In the current `gemini/batch-prediction/intro_batch_prediction.ipynb` notebook, the `gcs_batch_job.dest.gcs_uri` attribute from a completed job includes a trailing slash. When this URI is used with the notebook's f-string `glob` pattern, the resulting double slash breaks the path search, causing `fsspec.glob()` to fail to retrieve the `predictions.jsonl` file.

Could this issue be resolved by using `.rstrip('/')` on the URI before concatenation?

### Relevant log output

```shell
fs = fsspec.filesystem("gcs")

# Since this pattern includes a double slash, file_paths will be an empty list.
file_paths = fs.glob(f"{gcs_batch_job.dest.gcs_uri}/*/predictions.jsonl")

if gcs_batch_job.state == "JOB_STATE_SUCCEEDED":
# Load the JSONL file into a DataFrame
df = pd.read_json(f"gs://{file_paths[0]}", lines=True)

df = df.join(pd.json_normalize(df["response"], "candidates"))
display(df)
```

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