Type 2: Add database_name to ConnectionItem properties

[james-camacho-tel360]

Description

When creating a datasource through the Tableau Cloud UI, if you specify the connnector to be an Azure SQL Database you are allowed to specify the database name:

That database property is not available anywhere in tableauserverclient that I can find (unless it can be specified in the server_address, but haven't had any success with that so far). This is important for us since we are trying to create automation to deploy our data sources from our development website to our Production website, with our respective servers / databases updated in the process.

[jacalata]

FYI: while investigating #1807 we found that the read side of this fix is currently a no-op. The Tableau REST API doesn't emit dbName on the <connection> response element for any connector type, so ConnectionItem.database_name will always come back None after populate_connections(), even though the property exists. The write side (setting connection.database_name = "..." and publishing) works as intended.

If you need to read the database name back — or Oracle service, Snowflake schema, and similar connector-specific attributes — see #1807 for the workarounds (download + tableaudocumentapi for one-connection detail, or the Tableau Metadata API for batch reads). #1807 is now the tracker for the underlying gap; subscribe there for updates.