Fix button style

...etchat-mentions-flextab/client/views/mentionsFlexTab.html

...s/rocketchat-message-pin/client/views/pinnedMessages.html

...rocketchat-message-star/client/views/starredMessages.html

packages/rocketchat-theme/assets/stylesheets/base.less

...etchat-theme/assets/stylesheets/utils/_colors.import.less

packages/rocketchat-ui-admin/admin/users/adminUsers.coffee

.../rocketchat-ui-flextab/flex-tab/tabs/messageSearch.coffee

...es/rocketchat-ui-flextab/flex-tab/tabs/messageSearch.html

...ocketchat-ui-flextab/flex-tab/tabs/uploadedFilesList.html

packages/rocketchat-ui-login/login/form.html

packages/rocketchat-ui-message/message/messageBox.coffee

packages/rocketchat-ui-message/message/messageBox.html

packages/rocketchat-ui/views/app/room.coffee