backend: merge migration 3 into migration 1

twenty-backend/lib/twenty-backend/migration/1_create_projects.rb

@@ -7,6 +7,7 @@ class CreateProjects < ActiveRecord::Migration[7.1]
       t.string :path, null: false
       t.timestamps
     end
+    add_index :projects, [:name, :path], unique: true
   end
 
   def down

twenty-backend/lib/twenty-backend/migration/3_add_unique_index_to_projects.rb

@@ -1,11 +0,0 @@
-# frozen_string_literal: true
-
-class AddUniqueIndexToProjects < ActiveRecord::Migration[7.1]
-  def up
-    add_index :projects, [:name, :path], unique: true
-  end
-
-  def down
-    remove_index :projects, [:name, :path], unique: true
-  end
-end