fix: request to remote server not sent in case of fresh installation

[huzaifaiftikhar]

1. If Appium desktop is installed and we add a cloud provider then the "Attach to session" tab doesn't list any running sessions. This happens because the request to the remote server is never sent as the host, port & the path for the selected server type is not yet defined in the session variable. These values are populated only once we trigger a new session via AD for the newly added cloud provider, as it was only being set in the NEW_SESSION_REQUESTED event.
2. To fix the above issue I have created a method getServerInfo that returns the server information for the currently selected server type. This method either returns the values from the session variable or returns the default value.
3. The method getServerInfo is also used for both the NEW_SESSION_REQUESTED and GET_SESSIONS_REQUESTED events.
4. For reproducing on an already installed AD on macOS, run the following command rm ~/Library/Application\ Support/appium-desktop/Settings (⚠️ This will remove the saved settings so it might be better to take a backup of this file). After deleting restart AD -> add a cloud provider -> go to "Attach to Session" tab -> click on refresh button. Even if there are running sessions for your account on the remote server AD fails to list them.

[huzaifaiftikhar]

@KazuCocoa Can you review this as well?

[KazuCocoa]

Yes, I would do but haven't done yet.

[KazuCocoa]

Seems good, overall. Will merge this soon