[C++][Arrow Flight SQL ODBC] Running multiple tests with logging is not supported

### Describe the enhancement requested

Currently, `StartArrowLog` will be called multiple times in ODBC tests, and this can potentially be a problem because `StartArrowLog` is meant to be called once in a program. There is no current solution as Arrow's logging framework doesn't have an API to indicate if the logging framework is enabled or not. And `StartArrowLog` is called at `SQLAllocEnv` when the environment handle is allocated, not at connection level, so there is no way for user to indicate whether or not the driver is being tested.

While we don't have a permanent solution for this, here are some workarounds:

1. Do not enable logging when tests are run. I.e., remove the logging environment variable
2. Optional: Add a way for user to pass logging level in test program.

Note: the current approach only impacts tests. BI tools generally keep one connection alive, so it should not encounter those issue.

### Component(s)

C++, FlightRPC