Apply Layout/LeadingBlankLines rubocop rule

This rule is pretty obvious. However, we weren't following it in a
couple of places.

.rubocop.yml

@@ -70,6 +70,9 @@ Layout/IndentationConsistency:
 Layout/IndentationWidth:
   Enabled: true
 
+Layout/LeadingBlankLines:
+  Enabled: true
+
 Layout/MultilineBlockLayout:
   Enabled: true
 

app/models/budget_administrator.rb

@@ -1,4 +1,3 @@
-
 class BudgetAdministrator < ApplicationRecord
   belongs_to :budget
   belongs_to :administrator

app/models/custom/verification/residence.rb

@@ -1,4 +1,3 @@
-
 require_dependency Rails.root.join("app", "models", "verification", "residence").to_s
 
 class Verification::Residence