Run all user examples in CI

**Is your feature request related to a problem or challenge? Please describe what you are trying to do.**

Per a comment from @mesejo in #880 it would be helpful to run user examples in CI to ensure that our examples stay up to date with any breaking changes in the API.

**Describe the solution you'd like**

Update all user examples if necessary and add code to run them as part of CI.

**Describe alternatives you've considered**

We could leave as is, but this seems like a very good idea.

**Additional context**

This is already being done for TPC-H queries and we can re-use the generated dataset that is already created in CI. Here is where the tests are being run: https://github.com/apache/datafusion-python/blob/main/examples/tpch/_tests.py