Fix Back to Sign in url on confirmation form

[StasKozar]

Fix Back to Sign in url on confirmation form

Description

Added login url to Back to Sign in link

Fixed Issues (if relevant)

1. Storefront Back to Sign in button does not work as expected #12715: Issue title Storefront Back to Sign in button does not work as expected

Manual testing scenarios

Preconditions

Magento is installed from 2.2-develop branch
Set Require Emails Confirmation = Yes at Stores > Configuration > Customers > Customer Configuration
Steps to reproduce

Go to Storefront as a guest
Start creating new customer
Fill in all the required fields
Click Create an Account
Click click here from message `Please check your email for the confirmation link or click here for a new link
Click Back to Sign In button
Expected result

Customer is redirected to Sign In form

Actual result

Page is just reloaded

Contribution checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds on Travis CI are green)

[sidolov]

Hi @StasKozar , please, sign license CLA and I will continue delivery process

[StasKozar]

Hi @sidolov , done.

[sidolov]

Hi @StasKozar , consider to port this solution for 2.3 version