[BUG] [UI] Background height is not equal for highlighted word

[cyclops24]

Hi,
When we use highlight word feature, background height is not equal for highlighted word:

[cyclops24]

Part of #8175

[cyclops24]

@karlprieb, @ggazzo I found issue but before create a PR to fix this I have one question?
Why we need this padding-top? I want remove this line to fix this issue.

Rocket.Chat/packages/rocketchat-theme/client/imports/general/base_old.css

Line 3231 in 76d2061

padding-top: 10px;