docs: fix calendar enable environmental variable (twentyhq#5417)

Hi twenty team,
Thanks for making such a great product, it's a pleasure to use and see
the rapid development.
@charlesBochet helped me find this error in my setup

packages/twenty-docs/docs/start/self-hosting/self-hosting.mdx

@@ -69,7 +69,7 @@ import TabItem from '@theme/TabItem';
 
 <OptionTable options={[
     ['MESSAGING_PROVIDER_GMAIL_ENABLED', 'false', 'Enable Gmail API connection'],
-    ['CALENDAR_PROVIDER_GMAIL_ENABLED', 'false', 'Enable Google Calendar API connection'],
+    ['CALENDAR_PROVIDER_GOOGLE_ENABLED', 'false', 'Enable Google Calendar API connection'],
     ['AUTH_GOOGLE_APIS_CALLBACK_URL', '', 'Google APIs auth callback'],
     ['AUTH_PASSWORD_ENABLED', 'false', 'Enable Email/Password login'],
     ['AUTH_GOOGLE_ENABLED', 'false', 'Enable Google SSO login'],
@@ -208,4 +208,4 @@ import TabItem from '@theme/TabItem';
     ['CAPTCHA_DRIVER', '', "The captcha driver can be 'google-recaptcha' or 'turnstile'"],
     ['CAPTCHA_SITE_KEY', '', 'The captcha site key'],
     ['CAPTCHA_SECRET_KEY', '', 'The captcha secret key'],
-]}></OptionTable>
+]}></OptionTable>