Reduce contrast on search bar colours.

Red/green contrast for hovering over errors in search bar may present an
issue for colour blind users. Reduce contrast to improve UX.

Bug: b/200150386

Test: upload a trace with errors and see the display. Example trace on
bug.

Change-Id: I9648fd0bce904c2c7bd13d0600d8dc58280fe7ab
1 file changed