Prevent search-form-by-click input wrapping

From gitlab-org/gitlab!61413 (comment 572867783)

We should probably fix this in gitlab-ui by making flex: no-wrap for the input container. And also remove the right padding when the input is empty.

Screen_Shot_2021-05-17_at_11.22.26_am

If there is width: 100% set on .form-control (which we do in a few places), then the search button in the search-form-by-click component wraps, as shown in this screenshot inside the "fix wrapping" box:

screenshot showing faulty wrapping

Edited by Simon Knox