Revert "feat: Support Azure single-tenant application using the Graph… (#7436)

app/mailers/conversation_reply_mailer_helper.rb

@@ -23,7 +23,6 @@ module ConversationReplyMailerHelper
 
   def ms_smtp_settings
     return unless @inbox.email? && @channel.imap_enabled && @inbox.channel.provider == 'microsoft'
-    return ms_graph_settings if ENV.fetch('AZURE_TENANT_ID', false)
 
     smtp_settings = {
       address: 'smtp.office365.com',
@@ -41,15 +40,6 @@ module ConversationReplyMailerHelper
     @options[:delivery_method_options] = smtp_settings
   end
 
-  def ms_graph_settings
-    graph_settings = {
-      token: @channel.provider_config['access_token']
-    }
-
-    @options[:delivery_method] = :microsoft_graph
-    @options[:delivery_method_options] = graph_settings
-  end
-
   def set_delivery_method
     return unless @inbox.inbox_type == 'Email' && @channel.smtp_enabled