🚨(frontend) remove redundant undefined type or optional specifier

Fix TypeScript warning by removing either 'undefined' type annotation
or '?' optional specifier where both were redundantly specified.

src/frontend/src/features/rooms/components/join/ToggleDevice.tsx

@@ -11,7 +11,7 @@ import { useSnapshot } from 'valtio'
 import { permissionsStore } from '@/stores/permissions'
 
 type ToggleDeviceProps<T extends ToggleSource> = UseTrackToggleProps<T> & {
-  track?: LocalAudioTrack | LocalVideoTrack | undefined
+  track?: LocalAudioTrack | LocalVideoTrack
   source: ToggleSource
   variant?: NonNullable<ButtonRecipeProps>['variant']
 }

src/frontend/src/features/rooms/livekit/components/controls/SelectToggleDevice.tsx

@@ -28,7 +28,7 @@ import {
 
 type SelectToggleDeviceProps<T extends ToggleSource> =
   UseTrackToggleProps<T> & {
-    track?: LocalAudioTrack | LocalVideoTrack | undefined
+    track?: LocalAudioTrack | LocalVideoTrack
     initialDeviceId?: string
     onActiveDeviceChange: (deviceId: string) => void
     source: ToggleSource