Change interaction modal in web UI (#26075)

Co-authored-by: Eugen Rochko <eugen@zeonfederated.com>

app/lib/webfinger_resource.rb

@@ -11,6 +11,8 @@ class WebfingerResource
 
   def username
     case resource
+    when %r{\A(https?://)?#{instance_actor_regexp}/?\Z}
+      Rails.configuration.x.local_domain
     when /\Ahttps?/i
       username_from_url
     when /@/
@@ -22,6 +24,13 @@ class WebfingerResource
 
   private
 
+  def instance_actor_regexp
+    hosts = [Rails.configuration.x.local_domain, Rails.configuration.x.web_domain]
+    hosts.concat(Rails.configuration.x.alternate_domains) if Rails.configuration.x.alternate_domains.present?
+
+    Regexp.union(hosts)
+  end
+
   def username_from_url
     if account_show_page?
       path_params[:username]