Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a bug report that matches the one I want to file, without success.

Electron Version

18.0.1 x64

What operating system are you using?

Windows

Operating System Version

win7 sp1 x64

What arch are you using?

x64

Last Known Working Electron version

4.2

Expected Behavior

since user_data_dir is not multi-instance safe

#22772 (comment)

and per the intent expressed here:

#22772 (comment)
#22772 (review)

if the defaultSession is not needed by the app (when it uses a memory or persisted partition) the defaultSession should not be created, but more importantly persisted (which makes the app multi-instance unsafe)

Actual Behavior

the defaultSession is always created and persisted

run the following app

'use strict';

const {app, BrowserWindow, session} = require('electron'),
      path = require('path');

let win;

app.setPath('userData', path.join(__dirname, `user_data_${process.versions.chrome.split('.')[0]}`));

app.once('ready', () => {

  win = new BrowserWindow({
    webPreferences: {
      partition: 'memory_partition_1',
    },
  });

});

the user_data dir is filled with the persisted defaultSession not used by the app

Testcase Gist URL

No response

Additional Information

No response