The single PostgreSQL server is broken after adding credential with the wrong username/password and configure the firewall

[v-ruizh]

OS: Win10
Build Version: 20220308.1
Regression: Not a Regression

Repro Steps:

1. Create a single PostgreSQL server in portal.
2. Expand this single PostgreSQL server in VS Code --> Drill down database "postgres".
3. Click "Enter server credentials to connect to..." --> Enter a wrong username and password.

Expect:
Fail to add credentials to this single PostgreSQL server with an error, such as:

Actual:
Succeed to add credentials to this PostgreSQL server without any error.
Continue to configure firewall by clicking "Configure firewall to connect to...", this single PostgreSQL server is broken.

More Info:

1. This issue does not reproduce for the flexible PostgreSQL server.
2. This issue also reproduces on the previous released Azure Databases extension 0.18.1.