Function derive_connect_properties_for_cdc_table 

pub(crate) fn derive_connect_properties_for_cdc_table(
    source_with_properties: &WithOptionsSecResolved,
    external_table_name: String,
) -> Result<(WithOptionsSecResolved, String)>

Derive the connect properties of a CDC table from the properties of its source and the external_table_name in its TABLE '...' clause.

Returns (connect_properties, external_table_name) where external_table_name keeps the user’s spelling:

• For SQL Server: ‘schema.table’ (2 parts) gets the database name of the source prepended, so that it names the table the same way as Debezium’s topic, ‘database.schema.table’.
• For MySQL/Postgres: Returns the original external_table_name unchanged.