Remove unused constants from App.tsx

src/app/App.tsx

@@ -229,8 +229,6 @@ import {
   DEFAULT_SOUND_EMITTER_AUDIO_ASSET_ID,
   DEFAULT_SOUND_EMITTER_VOLUME,
   DEFAULT_SCENE_ENTRY_YAW_DEGREES,
-  DEFAULT_SCENE_EXIT_PROMPT,
-  DEFAULT_SCENE_EXIT_RADIUS,
   DEFAULT_SOUND_EMITTER_REF_DISTANCE,
   DEFAULT_SOUND_EMITTER_MAX_DISTANCE,
   DEFAULT_TELEPORT_TARGET_YAW_DEGREES,
@@ -261,7 +259,6 @@ import {
   createPlayerStartMovementTemplate,
   createPlayerStartEntity,
   createSceneEntryEntity,
-  createSceneExitEntity,
   createSoundEmitterEntity,
   createSpotLightEntity,
   createTeleportTargetEntity,