[Docs] Bug: Wrong property keys in the Arrow Flight JDBC Driver documentation

### Describe the bug, including details regarding any error messages, version, and platform.

In the documentation page of the Arrow Flight SQL JDBC Driver, there is an issue where the parameters table and the example are contradicting each other w.r.t the authentication property keys.

The example will use `username` in the Connection String meanwhile the table says that `user` is the property key for authentication.

`username` is the correct one and the table has outdated/wrong information.

### Component(s)

Documentation