[Glitch] Remove unused iOS agent sniffing function

Port 224d458f7e to glitch-soc

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

app/javascript/flavours/glitch/is_mobile.ts

@@ -27,10 +27,6 @@ export const layoutFromWindow = (layout_local_setting : string): LayoutType => {
   }
 };
 
-// eslint-disable-next-line @typescript-eslint/ban-ts-comment
-// @ts-expect-error
-const iOS = /iPad|iPhone|iPod/.test(navigator.userAgent) && window.MSStream != null;
-
 const listenerOptions = supportsPassiveEvents ? { passive: true } : false;
 
 let userTouching = false;
@@ -44,5 +40,3 @@ const touchListener = () => {
 window.addEventListener('touchstart', touchListener, listenerOptions);
 
 export const isUserTouching = () => userTouching;
-
-export const isIOS = () => iOS;