[Glitch] Visibility Modal fixes

Port 4df50b9c7e to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>

app/javascript/flavours/glitch/components/dropdown_selector.tsx

@@ -98,13 +98,13 @@ export const DropdownSelector: React.FC<Props> = ({
           break;
         case 'Tab':
           if (e.shiftKey) {
-            element =
-              nodeRef.current?.children[index + 1] ??
-              nodeRef.current?.firstElementChild;
-          } else {
             element =
               nodeRef.current?.children[index - 1] ??
               nodeRef.current?.lastElementChild;
+          } else {
+            element =
+              nodeRef.current?.children[index + 1] ??
+              nodeRef.current?.firstElementChild;
           }
           break;
         case 'Home':