Merge branch 'remove-callback' into 'master'

This MR removes AR before_validation callback in favor setter.

## Why was this MR needed?

Because setters is good practice to normalize model attributes instead AR callbacks. Because new object should be valid right after initialization. 
If it MR interested I can try to find other places where we can use setters.

See merge request !6763

CHANGELOG.md

@@ -10,6 +10,7 @@ Please view this file on the master branch, on stable branches it's out of date.
   - Use MergeRequestsClosingIssues cache data on Issue#closed_by_merge_requests method
   - Fix documents and comments on Build API `scope`
+  - Refactor email, use setter method instead AR callbacks for email attribute (Semyon Pupkov)
 ## 8.13.1 (unreleased)
   - Fix error in generating labels

app/models/email.rb

@@ -7,10 +7,8 @@ class Email < ActiveRecord::Base
   validates :email, presence: true, uniqueness: true, email: true
   validate :unique_email, if: ->(email) { email.email_changed? }
-  before_validation :cleanup_email
-
-  def cleanup_email
-    self.email = self.email.downcase.strip
+  def email=(value)
+    write_attribute(:email, value.downcase.strip)
   end
   def unique_email

spec/models/email_spec.rb

@@ -6,4 +6,9 @@ describe Email, models: true do
       subject { build(:email) }
     end
   end
+
+  it 'normalize email value' do
+    expect(described_class.new(email: ' inFO@exAMPLe.com ').email)
+      .to eq 'info@example.com'
+  end
 end