lesshat: remove "transform" mixin

packages/rocketchat-emoji/emojiPicker.less

packages/rocketchat-emoji/lesshat.less

...ages/rocketchat-livechat/app/client/stylesheets/main.less

...echat/app/client/stylesheets/utils/_keyframes.import.less

...ivechat/app/client/stylesheets/utils/_lesshat.import.less

packages/rocketchat-livechat/client/stylesheets/lesshat.less

...ages/rocketchat-livechat/client/stylesheets/livechat.less

packages/rocketchat-theme/client/imports/base.less

packages/rocketchat-theme/client/imports/keyframes.less

packages/rocketchat-theme/client/imports/lesshat.less

packages/rocketchat-theme/client/imports/rtl.less

packages/rocketchat-theme/server/lesshat.less