[FIX] account, portal: Adapt sidebar to be more responsive

1. Print & Download button can't be next to each other for some responsive
   reason:
   * On small computer screen size, there is not enough spaces so one button is
     pushed on a new line.
   * Button is also pushed on a new line even on big screen on other languages
     where the words can be a lot bigger (e.g: french "Imprimer/Télécharger").
   * Inverse problem appear if the words are smaller, both buttons won't fit
     all the available width and it will breaks the layout

2. There is an issue on big phone resolution in landscape mode.
   (iPhone X, Pixel 2 XL,..)
   Indeed, they are detected by bootstrap as 'MD' and not 'SM'.
   This was causing the sidebar to be displayed as for computer (fixed on the
   left side) but since there is not enough vertical space (height) in
   landscape, the bottom part of the sidebar would be hidden off the screen.

   Side effet: On small computer screen, it will now also be displayed like in
   mobile. This is in fact better since the invoice being displayed on
   col-sm-8 on these small screen would be completely squashed (since not
   enough width available to display things correctly).

opw-39876