[#817] removed deprecated border on sidebar and fix small visual bug cropping the bottom of the desktop sidebar (#852)

Co-authored-by: Camille Moussu <cmoussu@linagora.com>

src/components/Calendar/Calendar.styl

@@ -38,7 +38,6 @@
   margin-left 25%
 
 .sidebar
-  border-right 2px solid #f3f4f6
   width 270px
   height 100%
   flex-direction column

src/components/Calendar/Sidebar/DesktopSidebar.tsx

@@ -30,7 +30,8 @@ export const DesktopSidebar: React.FC<CalendarSidebarProps> = ({
           paddingLeft: 3,
           paddingRight: 2,
           width: '270px',
-          marginTop: isIframe ? 1 : '70px'
+          marginTop: isIframe ? 1 : '70px',
+          height: isIframe ? 'calc(100% - 8px)' : 'calc(100% - 70px)'
         },
         zIndex: 5
       }}