Message user search input focus is touching the search image

When using the search in the message drawer and going back the input field focus is touching the search image.

My Proposal as to a fix seen in the attached images and under https://github.com/TobiGa/moodle/commit/9e0e5fe8df323b61aa049f2f8f58a1fbb4c7a609

https://github.com/moodle/moodle/compare/master...TobiGa:MDL-67660-master-v2

basically a removal of the reduced padding and adding a border as to signify the non clickable area.

basically adding a little padding.