🚸(frontend) avoid displaying the effects option when not optimal

On unsupported browser showing this option whitout offering the
blur effects to the user would be quite frustrating.

At the moment, safari user cannot blur their background.

Also, avoid offering the option on mobile which are really
cpu-constrained devices.

src/frontend/src/features/rooms/components/Join.tsx

@@ -19,6 +19,7 @@ import {
 } from '../livekit/components/effects/EffectsConfiguration'
 import { usePersistentUserChoices } from '../livekit/hooks/usePersistentUserChoices'
 import { BackgroundBlurFactory } from '../livekit/components/blur'
+import { isMobileBrowser } from '@livekit/components-core'
 
 const onError = (e: Error) => console.error('ERROR', e)
 
@@ -30,6 +31,10 @@ const Effects = ({
   const [isDialogOpen, setIsDialogOpen] = useState(false)
   const openDialog = () => setIsDialogOpen(true)
 
+  if (!BackgroundBlurFactory.isSupported() || isMobileBrowser()) {
+    return
+  }
+
   return (
     <>
       <Dialog