[Bug]: Invalid Link to Spanner Data Export in README (gemini/sample-apps/finance-advisor-spanner)

### File Name

https://github.com/GoogleCloudPlatform/generative-ai/blob/main/gemini/sample-apps/finance-advisor-spanner/README.md

### What happened?

I encountered an issue while following the instructions in the README to deploy the Finvest Spanner Demo Application. The link provided for importing data into the Spanner instance appears to be invalid.

### **Problem Details:**
The README includes a link to a Google Cloud Storage bucket that should contain the data export necessary for the Spanner instance. The specific link provided is:

https://storage.googleapis.com/github-repo/generative-ai/sample-apps/finance-advisor-spanner/spanner-fts-mf-data-export/

### Relevant log output

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct