Tweak u-highlight styles
Tweak u-highlight styles

1. Lose border in favour of simple background colour as it interfered with
   potential existing styling of the text.

2. Add padding and negative offset to give highlighted text some room while
   keeping the same position in contextual text.

uktrade/data-hub-fe-beta2,uktrade/data-hub-frontend,uktrade/data-hub-fe-beta2,uktrade/data-hub-frontend,uktrade/data-hub-frontend