fix modal in menu setting cannot be closed by pressing ESC

[``* `#15406` modal in menu setting cannot be closed by pressing ESC``](http://www.openproject.org/work_packages/15406)

[``* `#15407` focus lost after closing modal in menu settings``](http://www.openproject.org/work_packages/15407)

I changed a bower.json dependency to my own repository so a bower clean cache and a bower install might be needed
Prefer single-quoted strings when you don't need string interpolation or special symbols.