Default ConnectTimeout option should be 30 instead of 15

[kburtram]

Steps to Reproduce:

1. Add a connection using Connection Dialog and don't change any advanced options

Expected: Settings basically match what's in ADS, specifically Connect Timeout should default to 30 seconds.

Actual: Timeout defaults to 15 seconds, which is too short in many scenarios. The lower timeouts cause increased failures in environments with slow network, or on instances with high load. I'd probably remove "applicationName" from the settings too, since the application can set this at runtime, assume the user doesn't want to override it, but that's not really a problem the same way as the short timeout.

For example, here's a 'default' connection snippet:

  {
      "authenticationType": "SqlLogin",
      "connectTimeout": 15,
      "applicationName": "vscode-mssql",
      "profileName": "",
      "server": "localhost",
      "user": "sa",
      "password": "",
      "database": "",
      "trustServerCertificate": true
  }

[Benjin]

Both the applicationName and connectTimeout default changes were explicitly requested by @croblesm in #18152.

Happy to bump the connectTimeout back to 30, but I do remember users in one of the user sessions that Carlos ran explicitly talking about how they prefer a default value for applicationName to be set in their tools.

[Benjin]

I'm using this issue for the default timeout length, but created #18592 to clean up the config entries later. I'll fold that into my connection management updates.

[Benjin]

Decision is to revert timeout at 30 seconds, but to look into flexing the number of retries.