Remove CWBI Test URL from the Examples

[krowvin]

We received an email from a third party that had issues fetching data with CWMS Python.

They were getting a 403 error when attempting to query.

It was determined that they used the examples to build their query and in those examples we use CWBI-TEST (probably from the workshop).

Please consider updating these examples to show the national/public API URL (https://cwms-data.usace.army.mil/cwms-data):

https://github.com/search?q=repo%3AHydrologicEngineeringCenter%2Fcwms-python%20cwbi&type=code