Fixed Style/Semicolon RuboCop offense

Change-Id: Ib01751f81e921beb3c7e157f9e8037859eb1b3f6
See: https://github.com/bbatsov/ruby-style-guide#no-semicolon
Bug: T117984

.rubocop_todo.yml

@@ -17,13 +17,6 @@ Style/GlobalVars:
   Exclude:
     - 'tests/browser/features/step_definitions/mmv_performance_steps.rb'
 
-# Offense count: 1
-# Cop supports --auto-correct.
-# Configuration parameters: AllowAsExpressionSeparator.
-Style/Semicolon:
-  Exclude:
-    - 'tests/browser/features/step_definitions/mmv_navigation_steps.rb'
-
 # Offense count: 79
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, SupportedStyles.

tests/browser/features/step_definitions/mmv_navigation_steps.rb

@@ -10,7 +10,7 @@ end
 
 When /^I press the browser back button$/ do
   # $browser.back doesn't work for Safari. This is a workaround for https://code.google.com/p/selenium/issues/detail?id=3771
-  on(E2ETestPage).execute_script("window.history.back();");
+  on(E2ETestPage).execute_script("window.history.back();")
 end
 
 Then /^the image and metadata of the next image should appear$/ do