[C++] Copy connection string properly in SQLDriverConnectW in Arrow Flight SQL ODBC

[alinaliBQ]

Describe the enhancement requested

We need to copy connection string properly in SQLDriverConnectW in the ODBC driver according to spec: https://learn.microsoft.com/en-us/sql/odbc/reference/syntax/sqldriverconnect-function?view=sql-server-ver16.

1. outConnectionString needs to be properly null-terminated
2. In scenarios where the DSN window is displayed (see spec), outConnectionString needs to include the values entered in the DSN window.
3. Check if password needs to be masked in the outConnectionString output parameter. This can be done by checking SQLDriverConnectW behavior of the SQL Server ODBC driver.
   i. If the password needs to be masked, update the implementation of SQLDriverConnectW to mask the password during copy

Parent issue: #30622

Component(s)

FlightRPC