multiple buttons should be inline

Since we use "display:flex" on the buttons, the button itself is block not inline, so they stack as seen here:

I believe this can be fixed like so: https://lab.civicrm.org/artfulrobot/riverlea/-/blob/a2f3d3dcca1c925d762279cc734d6fb4a97edd4f/streams/thames/css/civicrm.css#L72-77

using display: inline-flex for buttons. Also adding some vertical padding to avoid no-gap top-bottom situations.