Impacted versions: 11.0

Steps to reproduce: Just test on [Runbot](http://289106-11-0-b95622.runbot13.odoo.com/web?debug=1#id=&view_type=form&model=res.config.settings&action=110&menu_id=4) --> Uninstall website module --> Go to the Configuration page for any module > Make any changes and save it.

Current behavior: [Odoo Server Error - Validation Error]


![](https://image.prntscr.com/image/Gx3lGxX4Qg6lsxAhGxL5SQ.png)

Even the field which was added by website module (website_id) is also not removed from the database.

![](https://image.prntscr.com/image/Wn1C8lPdTg6frBLga0ZVqQ.png)

Expected behavior: Configuration should be applied.

Video/Screenshot link (optional):


addons/website/models/res_config_settings.py
_inherit = 'res.config.settings'
    def _default_website(self):
        return self.env['website'].search([], limit=1)
    website_id = fields.Many2one('website', string="website", default=_default_website, required=True)
    website_name = fields.Char('Website Name', related='website_id.name')
    language_ids = fields.Many2many(related='website_id.language_ids', relation='res.lang')
    language_count = fields.Integer(string='Number of languages', compute='_compute_language_count', readonly=True)
    default_lang_id = fields.Many2one(string='Default language', related='website_id.default_lang_id', relation='res.lang', required=True)
    default_lang_code = fields.Char('Default language code', related='website_id.default_lang_code')
    google_analytics_key = fields.Char('Google Analytics Key', related='website_id.google_analytics_key')
    google_management_client_id = fields.Char('Google Client ID', related='website_id.google_management_client_id')
    google_management_client_secret = fields.Char('Google Client Secret', related='website_id.google_management_client_secret')
    cdn_activated = fields.Boolean('Use a Content Delivery Network (CDN)', related='website_id.cdn_activated')
    cdn_url = fields.Char(related='website_id.cdn_url')
    cdn_filters = fields.Text(related='website_id.cdn_filters')
    module_website_version = fields.Boolean("A/B Testing")
    favicon = fields.Binary('Favicon', related='website_id.favicon')
    
    
    google_maps_api_key = fields.Char(string='Google Maps API Key')
    has_google_analytics = fields.Boolean("Google Analytics")
    has_google_analytics_dashboard = fields.Boolean("Google Analytics in Dashboard")
    has_google_maps = fields.Boolean("Google Maps")
    auth_signup_uninvited = fields.Selection([
        ('b2b', 'On invitation (B2B)'),
        ('b2c', 'Free sign up (B2C)'),
    ], string='Customer Account')
    @api.onchange('has_google_analytics')
    def onchange_has_google_analytics(self):