[Glitch] Fix RTL layout not being RTL within the columns area

Port b44ae7d284 to glitch-soc

Signed-off-by: Thibaut Girka <thib@sitedethib.com>

app/javascript/flavours/glitch/styles/rtl.scss

@@ -43,6 +43,10 @@ body.rtl {
     left: 10px;
   }
 
+  .columns-area {
+    direction: rtl;
+  }
+
   .column-header__buttons {
     left: 0;
     right: auto;