review: update styles + aria hidden

src/AppBar.tsx

@@ -68,8 +68,8 @@ export const AppBar: FC<Props> = ({ children }) => {
         >
           <LeftNav>
             <Tooltip label={t("common.back")}>
-              <IconButton onClick={onBackClick}>
-                <CollapseIcon />
+              <IconButton size="24px" onClick={onBackClick}>
+                <CollapseIcon aria-hidden />
               </IconButton>
             </Tooltip>
           </LeftNav>

src/button/Button.tsx

@@ -140,7 +140,7 @@ export const SettingsIconButton: FC<SettingsIconButtonProps> = (props) => {
   return (
     <Tooltip label={t("common.settings")}>
       <IconButton {...props}>
-        <Icon />
+        <Icon aria-hidden />
       </IconButton>
     </Tooltip>
   );