DEV: Remove use of deprecated methods (#19486)

app/models/user.rb

@@ -252,7 +252,7 @@ class User < ActiveRecord::Base
   end
 
   scope :filter_by_username_or_email, ->(filter) do
-    if filter =~ /.+@.+/
+    if filter.is_a?(String) && filter =~ /.+@.+/
       # probably an email so try the bypass
       if user_id = UserEmail.where("lower(email) = ?", filter.downcase).pluck_first(:user_id)
         return where('users.id = ?', user_id)

spec/lib/stylesheet/manager_spec.rb

@@ -929,7 +929,7 @@ RSpec.describe Stylesheet::Manager do
 
       after do
         path = Stylesheet::Manager.send(:manifest_full_path)
-        File.delete(path) if File.exists?(path)
+        File.delete(path) if File.exist?(path)
       end
 
       it "returns a hash" do