fix: Identity JSON response header (#6326)

app/controllers/microsoft_controller.rb

@@ -1,5 +1,17 @@
 class MicrosoftController < ApplicationController
+  after_action :set_version_header
+
   def identity_association
-    render layout: false
+    microsoft_indentity
+  end
+
+  private
+
+  def set_version_header
+    response.headers['Content-Length'] = { associatedApplications: [{ applicationId: @identity_json }] }.to_json.length
+  end
+
+  def microsoft_indentity
+    @identity_json = ENV.fetch('AZURE_APP_ID', nil)
   end
 end