feat: Control the allowed login methods via Super Admin (#12892)

- Control the allowed authentication methods for a chatwoot installation
via super admin configs. [SAML, Google Auth etc]
------
[Codex
Task](https://chatgpt.com/codex/tasks/task_e_6917d503b6e48326a261672c1de91462)

---------

Co-authored-by: Pranav <pranav@chatwoot.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

config/installation_config.yml

@@ -438,8 +438,23 @@
   value:
   locked: false
   description: 'The redirect URI configured in your Google OAuth app'
+- name: ENABLE_GOOGLE_OAUTH_LOGIN
+  display_title: 'Enable Google OAuth login'
+  value: true
+  locked: false
+  description: 'Show Google OAuth as a login option when credentials are configured'
+  type: boolean
 ## ------ End of Configs added for Google OAuth ------ ##
 
+## ------ Configs added for SAML SSO ------ ##
+- name: ENABLE_SAML_SSO_LOGIN
+  display_title: 'Enable SAML SSO login'
+  value: true
+  locked: false
+  description: 'Show SAML SSO as a login option. Cannot be disabled if any users are using SAML authentication.'
+  type: boolean
+## ------ End of Configs added for SAML SSO ------ ##
+
 ## ------ Configs added for Cloudflare ------ ##
 - name: CLOUDFLARE_API_KEY
   display_title: 'Cloudflare API Key'