Connection string is not properly forwarded to connection Test

[1nf0rmagician]

Describe the bug
When configuring the NpgsqlConnection in the Command Center Web UI, the connection that is established to test the configuration does not propperly recieve the user from the connection string, but uses the default postgres user instead. The test connection is opened here

To Reproduce
Steps to reproduce the behavior:

1. Setup a PostgreSql database without a postgres user
2. Go to the Command Center interface
3. Configure any postgres database conenction with a valid user for your database
4. Click Save
5. An error indicator is shown that no connection to the databsae was possible

Expected behavior
The connection string should be used propperly to evaluate the connection to the database