Wait to signal to the extHostTerminalService that the terminal is opened until the terminal has a name.

[alexr00]

Also added a change listener for title. Fixes #53057

[alexr00]

Tested with

const shell = vscode.window.createTerminalRenderer('fake shell');
shell.write('Type and press enter to echo the text\r\n\r\n');
shell.terminal.show();
setTimeout(() => {
    shell.name = 'new name';
    setTimeout(() => console.log(shell.terminal.name), 500);
}, 500);

and by checking the terminal name in onDidOpenTerminal

[Tyriar]

As discussed, I think we can just remove this and always send titles over from the main side.