Change generate_data to use pd.ArrowDtype

**Feature request**

**Before submitting**
Please check the following:

- [ ] I have described the purpose of the suggested change, specifying what I need the enhancement to accomplish, i.e. what problem it solves.
- [ ] I have included any relevant links, screenshots, environment information, and data relevant to implementing the requested feature, as well as pseudocode for how I want to access the new functionality.
- [ ] If I have ideas for how the new feature could be implemented, I have provided explanations and/or pseudocode and/or task lists for the steps.

Start by locating the generate_data entry point and reviewing how it currently assigns or represents data types. Check the surrounding tests, if present, for dtype expectations and run them before making changes. Done means generate_data uses pandas ArrowDtype without breaking its existing behavior.

Written by the indexing model from the issue text.