Views block description is double-escaped if display name is set

Problem/Motivation

Views block descriptions are double escaped in the block configuration page if the views block has a custom display name.

Steps to reproduce

1. Install Drupal
2. Create a views block with a character such as & in the block title and set a custom 'Display name'. Note that the character can be in the block title or display name, the double encoding will occur as long as the display name is set.
   
3. Go to Structure > Block layout and place the block
4. See that the block description is double escaped
   

Proposed resolution

Don't double escape the block description

Remaining tasks

• Write a patch with tests
• Review

User interface changes

N/A

API changes

N/A

Data model changes

N/A

Release notes snippet

N/A