Merge pull request from GHSA-vm39-j3vx-pch3

* Prevent different identities from a same SSO provider from accessing a same account

* Lock auth provider changes behind `ALLOW_UNSAFE_AUTH_PROVIDER_REATTACH=true`

* Rename methods to avoid confusion between OAuth and OmniAuth

app/controllers/auth/omniauth_callbacks_controller.rb

@@ -5,7 +5,7 @@ class Auth::OmniauthCallbacksController < Devise::OmniauthCallbacksController
 
   def self.provides_callback_for(provider)
     define_method provider do
-      @user = User.find_for_oauth(request.env['omniauth.auth'], current_user)
+      @user = User.find_for_omniauth(request.env['omniauth.auth'], current_user)
 
       if @user.persisted?
         LoginActivity.create(