fix: correct pymssql connection encryption parameter

[albertoleonor]

Summary

Fixes an issue where setting MSSQL_ENCRYPT to "true" (or automatic Azure SQL detection) fails with a connection error:
TypeError: connect() got an unexpected keyword argument 'encrypt'

Details

• pymssql does not support the encrypt keyword parameter in connect(), nor does it support connection string options appended to the host/server string (which causes FreeTDS to fail hostname resolution).
• The correct parameter supported by pymssql (version 2.2.8+) is encryption, which accepts string values: 'off', 'request', or 'require'.
• This PR replaces the encrypt setting and server string appending with the correct encryption parameter (setting it to 'require' when encryption is desired and 'off' otherwise).
• Unit tests in tests/test_config.py have been updated to reflect the new encryption parameter format.